okay thanks! I've classed them on-time. thanks for the advices.

If you were intended to late class, you should do it when they were still gunners.
You should do it only for a particular reason.

As DeltaUCF said before, always class your UK gunners on time. Your accuracy will
suffer, but because of the accuracy bonus UK gives, your reload gunners will eventually
hit both reload and accuracy cap. =)

Your accuracy will suffer, but ever so briefly. The accuracy cap is much lower than the
reload cap, so you will hit that cap sooner. Hitting the cap means that no matter
how many more experts or vets you add, your true ability will not increase until you
hit the next level. You want as much reload ability as possible for UK since the reload
times are usually fairly long.

If you are playing for the long haul in UK, class on time.

ETA: For further reading, see:

http://tinyurl.com/299chy2

thanks for fast reply, but wouldn't my acc suffer?

Class them on time.

/thread.

:D