I'm currently using 11/11 gunners classed to ACC at Lvl65.
With 150 vets on these gunners you'll experience very comfortable spread with all at-level guns. The reload time is good, too.
And the later you class your gunners, the lighter your gunners will be. This is the way to keep my crew lighter as opposed to some other people who would rather class their gunners at-level and then reduce the rookie sailors.
(With 200% vet conversion events, 150 vets is not hard to get)