Many of you may already started to realize that the big huge ships are a little shy for their squad point cost. A full-armed corvette may cost 150-160 points, that is equivalent to 5-6 well-armed small ordnance carriers, capable to take out that huge ship without significant losses (see this).

A corvette's main role in the epic battle is to bear damage while shoting back with its many powerful weapons... but hey, how potent are those weapons?
- Single Turbolasers (Range 3-5): because the defender doubles the agility when defending against it, it can be effective against very low agility targets only (agi 0, maybe 1). Don't waste its shots against higher agility target unless very-very necessary. Very selective, huge risk equipping the ship with these. Uses huge amount of energy.
- Ion Cannon Battery (Range 2-4): can be used against (already-)shieldless small ship, despite does not deal adequate damage to them. Uses huge amount of energy.
- Quad Laser Cannons (Range 1-2): good short-range weapon, but when the enemy is in short range in high numbers, then something is already went wrong...
- Ordnance (with Ordnance Tubes modification): various missiles and torpedoes, in range 1-2-3, working only with Target Locks (so Weapon Engineer crew is a must have, even when you don't have to spend the TL to attack). Not easy to synchronize the various damage dealing type. Damage dealing capacity varies hugely on enemy ship types, and tend to attract other upgrades that makes your ship more expensive than it should be (Gunnery Team, Ordnance Expert, support ships). Works without energy, but useless after the TL-ing section crippled (mostly... some workaround exists, but those come with a drawback or cost, e.g. Dutch Vander or Shara Bey, XX-23 S-Thread Tracers, Targeting Synchronizer on a nearby ship, Targeting Coordinator). Due to the not too long range of the ordnance, the corvette is need to close up to the main battle, what is a risk.
- Primary weapon turret (Range 3-5): 4 dice (can be enhanced to 5). Powerful, but shot only once per turn, at least it seems to...

So, primary is strong, ordnance is very OK, the others are very situational/dubious...

Considering support ships
Esege Tuketu (K-Wing) with Recon Specialist (there is a debate whether the huge ship can use Esege's focus: https://community.fantasyflightgames.com/topic/185366-so-hortoncorvette-has-been-a-thing-but-esegecorvette or not: https://community.fantasyflightgames.com/topic/187918-huge-ship-rule-turned-on-its-head-cr-90-can-use-eseges-focus ) if it works, then works within Range 2, costs ~35 points [Ask for your opponent or Tournament Organizer!]
Shara Bey (ARC-170) (with Weapons Engineer): her 2 Target Locks may used by the huge ship, works within Range 2, ~35 points
M9-G8 astromech in friendly ship: may help to reroll attack die, but very circumstantial to use it effectively... so many drawbacks...
Bodhi Rook (U-Wing): when a friendly ship acquires a target lock, that can lock an enemy ship at Range 1-3 of any friendly ship, ~25+ points (this may replaces Sensor Team). Captain Kagi (Lambda) in the enemy team can ruin it.
Roark Garnet (HWK) -> makes the ship PS12, works within Range 3, ~20 points. Always worth it, it may award you one or more preventive killings a turn, and those killed ships cannot shot back.
Jan Ors (HWK) -> may boost one primary attack +1 attack die (once a turn), works within Range 3, ~30 points

Amongs those, Roark and Esege are huge help: the help range is over Range 1 (doesn't restrict each other's movements much), both can help other ships of the squad, too, and can equip TLT to keep themselves at strike range of the battle, presumably at Range 3.

Sidenote / Just to mention Imperial ships with similar effects:
Howlrunner (TIE/ln)-> one attack die (per attack, primary only) can be rerolled, needs to be at Range 1, ~20 points
Captain Jonus -(TIE/B)> two dice can be rerolled (per attack, secondary weapon only), needs to be at Range 1, ~25+ points
(Plenty of drawbacks come up: these two alone makes a Raider +50 point more expensive, and these ships are useless in the battle: hard to keep Range 1 when turning - did I mention that huge ships turning based on 30° steps, while small ones based on 45°? If you want to keep these buffs for a while, you have to keep these ships behind the huge ship, therefore they are far from the battle. If they are closer, then they are the enemy's primary targets, and won't live long. Nightmarish!)
Upsilon-class Shuttle (~40): Targeting Synchronizer (Tech) and Weapons Engineer (Crew), and the corvette with Sensor Team (or without it, as you please) and Targeting Coordinator: for 1 energy the coordinator gets a TL in Range 1-5), passes to the shuttle, where an other TL is assigned by the Weapons Engineer. After that, the corvette can TL as a regular action, aquiring 2 normal TLs. This case, the Raider's can use these 4 TLs when needed.

Measuring survivability
Seeing point-wise, a big huge ship worths its own cost, if the enemy of smaller ships with similar squad-point couldn't destroy it's reinforced full-health section with all the shots aimed at that. If that's not the case, then the big ship simply won't worth it.(It is my personal experience.)

The closer to 100 point the ship is, the better. This indicates a light-equipped corvette, that is not really worth by the enemy to make hard efforts to cripple. Or, they waste useful shots on an unworthy target... Both is OK for us.

OK, it's not worth to shot at it, but worth enough for us to bring it to the battle...

Weapons Engineer: 2 Target Locks, obvious.
Other action is always the reinforcing (the section that is in danger).
In this corvette-build you should opt for shoting last with cruise missiles, and miss! Althought you may roll additional attack dice, but don't do that: grants you additional primary attack.
Other upgrades considered:
Targetting Coordinator (4) - frees up a TL action, instead use an energy. You can aquire the same 2 TLs as a TL action. You may assign one of them to an other ship, but you may assign that to the corvette itself. Practically, it grants an additional coordinate action for 4 squad point plus an energy. Condtradicts to "slim corvette" theory. If needed, place it to the aft section to be able to Target Locking after the front is crippled.
IG-RM Thug Droids (1) - if you have free team slots, it's nice litte extension for almost free, and you can stack more than one.
Torpedoes: a TL must spent to fire torpedoo, and the 2 TLs are so scarce and needed to modify the attack... You never have enough TLs in this case.
Missiles: using the ones that don't need to spend the TL, theese come up:
Advanced Homong Missiles: limited to Range 2 only, 1 damage only (OK, it deals a critical damage whatsoever), week and/or very situational.
Cruise Missiles: you need to move straight 3 or 4 every turn to maximaze its attack value (which may drive you to wrong positions). Very situational.
Ion Pulse Missiles: deals 1 damage only and 2 ion tokens. Just week.
Harpoon Missiles (not realesed yet): a kind-of Assault Missile-like, but can fire back (would you destroy a Harpooned enemy ship when it is within your formation?) You need to have finishing shots with critical damage. Situational. Maybe good.
Homing Missiles: just what we need. Not excellent, but it will do.
You may forfeit the additional primary attack: remove Tantive IV (4) + Baze Malbus (3) + Cruise Missile (3) for a more potent missile - e.g. Homing Missile (5): 5 squad point saved this case.
Gunnery Team and Ordnance Team is very needed to modify slightly week results, but can be removed for retrieve 9 squad points.
Sensor Team (4): not a must-have in this configuration. Avoid it, and try to aim those targets that already Target Locket at Range 3.

Before your front section is killed, Target Lock 2 enemy ships that you anticipated to remaining in the battlefield long, and never spend those TLs again: this case, your aft section missile is always on.

Pros:
- This case, the energy manegement won't be an issue; you spend 2-3 per turn only (to strenghten primary attack and trigger Gunnery Team).
- 1 primary + 3 missile attacks, 2 of them can be rerolled (by TL) or modified by Han, Gunnery Team or Ordnance Experts.
- Easy to use.

Cons:
- Effective weapon range is 2-3 broadside (plus primary 3-5 round).
- Squad cost is not minimal.
- This setup marks the corvette as #1 target for the enemy.

 [See the Range 3-Range 4 distance between the corvette and the place of the battle]

Introducing an other approach, the Slim Gunboat

CR-90 fore & aft, 90 points (reset the setup)
Apply an Ion Cannon Battery (ICB) and Baze Malbus to be able to shot twice from the powerful primary weapon! (6+3 points)
That case, multiple Target Locks will be handy, employ a Weapon Engineer! (3 points)
To be able to TL at long range, a Sensor Team is needed. (4 points)
If ICB is used every round, and the two primary shot is enhanced to 5-dice attacks, a constant burning of 4 energy per turn occures, it is needed to upkeep the corvette's energy flow: this implies to bring:
Optimized Generators (5 points): +2 energy, when needed the most (that is, when the usage of the ICB burns energy fast). Energy management won't be an issue this case. 

Other upgrades that could have seemed useful:
Tibbana gas supplies (3 points): if used, then after the 2nd round of fire exchange, only if the next round's intended move is 2 bank or 4 forward. Since Optimized Generators used, no need to use this.
Supercharged Power Cell (3 points): nice addition, if equipped, fire it as soon as possible to lower the corvette's aggro* level. May worth it, but not essential.
Automated Protocols (5 points): by the time Reinforce and Recovery both needed, you will be short on energy, so reinforce won't help you, therefore, it will be so useless.
Avoid them, because all of them derails our cheap-ship aims! From the points spared here, enhance other ships of your squad!
Assign the Tantive IV (4) title and Han Solo(2) (Total: 117 points, getting expensive...) (It needs to re-organize crew placement to minimize the effect of the crippled front section.)

 So, what is my suggestion?

Managing the corvette in the setup:
(ship starting the battle with fully loaded energy on every energy-related cards, as per see: epic tournament rules)
Move.
Always load energy to uptop the ICB, then use Optimized Generators to gain back 2 energy.
Always reinforce the section that is endangered (mostly, the fore).
Target Lock 2 ships (use Weapon Engineers) that valuable targets with 5-dice modifyable primary attack. This is the toughest point of the handling sequence (targets should be alive when the corvette firing at them, presumably low/medium agility ships).
Shot with primary, increase weapon strength. You may use Han's ability, or spend Target Lock to reroll.
Shot with ICB: aim a high-agility, shieldless, stressed small ship (that may have focus or evade token, doesn't matter) - but won't be the ones which are Target Locked! (Why? Because it makes the enemy commender under high pressure! Letting a devastating hit going through or let an other attempt of powerful primary shot?) If it hits, good. If it misses, even better: with Baze Malbus, attempt another primary weapon attack against another ship (increase strength again, use Han's ability, or spend Target Lock to reroll, as you wish).
Repeat.

Maneuvering
The CR-90's primary weapon is a turret, usable in R3-R5 with 5 attack dice ("4" on paper).
Secondary armament only shots sideways, or "broadside". This makes hard to maneuver the ship and find valuable targets in Range 3-5, because you cannot go into the battle headways on: that should invite the enemy to lure around the ship in a Range-2 donut hole, and attack this ship's sections in short range. Try to avoid this, and keeping the distance from the place of the main engagement (the centre of the battle) by trying to circle around that place (desired distance: Range3-Range5).

Pros:
- Powerful primary weapon attacks that covers long ranges where smaller enemy ships are not a threat.
- Cheap setup.
- Not so threatening: enemy may picks other ships as #1 priority. (if not, then almost as hard to destroy as a 150-point corvette)

Cons:
- Enemy ships in short ranges need to be handled by escort ships.
- Requires practice of effective maneuvering.

Even I can't decide which setup is best. Can you?

Recommended discussion:
https://community.fantasyflightgames.com/topic/249525-community-project-epic/
Other smart tips for epic:
https://community.fantasyflightgames.com/topic/253825-epic-x-wing-questions/?do=findComment&comment=2873487

UPDATE:
IG-RM Thug Droids added. Thanks to T.Á. to raise my attention to this nice cheap upgrade; otherwise it would go under my radar.