AAW stat is not as important since most planes in GB are AAW immune. I would run atlanta since it has 2 additional Gun slots out of the 3 remods, thus 4 more shells in the air.
Remember escort gun turrets have 360 degree arc of fire, even when shooting at the superstructure.
Given a choice of US ships, I would choose the Cleveland since it has 10 combine R+T slots that can hold 5" or the 3" duals. The only downside is the high repair cost so dont let it sink. The CL engine III also gives it a good base speed, since escorts dont OH and of course it has good durability.
Omaha is a cheap substitute for the atlanta (8 R) but can only really hold the 3"70s.