Yep, small squads of rebels work great. Group up, select target, attack, regroup, attack..rinse and repeat. Three Y-Wings with 2-3 X-Wing escorts works ok. Better would be two attack squads, one in Y's, the other giving fighter escort.

X's use their twin torpedos to hit the gun towers giving a clear ground run. Y's are better swinging in from above IMO, with the X's staying low to have a greater view of the area. Easier to get in behind a Tie swinging up to meet the Y's then. Two squads working like that could probably take a tower in a couple passes, just remember to break off to regroup once losses get too heavy to become co-ordinated again.

Imps should also get in two squads, tower gunners and fighters. Towers should spot enemy fighters and not engage unless they are within easy distance, prevents TK's. TF's defend towers with greatest number of enemy fighters attacking and NEVER go head on unless you confident at far range. Have a couple lone wolfs patroling the trench for nubs trying to destroy it with towers still up, and for those hoping the towers will drop while they are in.

Bite my shiny metal Tie Fighter!