I'd actually NOT class them acc gunners, but reload, and without delay.

My RN gunners hit both caps around lvl 78, with 109 vets.

Do NOT class them Acc.

At lvl 42, choose reload.

The only reason to class UK gunners to ACC, is to use them for Blitz blockshot and then to get rid of them at lvl 61.
If you want to continue to use the gunners past level 60 and not be at a (big) disadvantage for most of the next 60 levels, class them Reload.

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)

Bve'd reload gunners with 12/13 base acc reach the acc cap around 14"lvl according to the old formula. 11 base adds about 2 levels to that.

And yeah, you won't have to go to 120 to cap reload on your acc gunners. But delaying classing by only 23 levels, doesn't save you from having to level quite a few levels more on your gunners to fully cap them, than if you would have gone the reload way.

I have elite reload gunners properly classed as reload (no delay) with 215 vets each in lvl 95. The spread is very good!!!!