Ok I have never seen anyone try to build this so I am thinking a 300 pt battle at least, broken up into 3 missions making a campaign.
Essentially how I think it should work is the first round being a xNumber of rounds where the rebels must protect a Gr-75 and a corvette , with upgrades on each and their squadron being up to but not exceeding 250 pts. The base ships would be free. The empire would get around 300 points for there assault.
The next wave is the though one, it's an Imperial defense of the Executor. Essentially like the one Star Destroyer assualt I have seen floating around here, where the rebels need to attack the 2 shield generators (large bases) being defended by turrets and the 300 pt imperial fleet. 300 V. 300 named pilots retire if killed. Another X number of rounds.
This would culminate in a strike at core, each side starting at 100 squad points and gaining 50 for each scenario they won, where a trench run with obstacles instead of guns must be made. Imperials must destroy rebels before they reach and destroy the core or lose.
What do you think? I know this is basic but will it work?