Always, always keep your sailors maxxed out.
Did I mention, always?
As someone mentioned above, you'll gain experts faster with full sailors. Not to
mention you'll save yourself *alot* of mission whoring in the future when you realize
you *need* those experts you should have been gaining all along.

recuits does add towards sailor ability, but it's not by a very large amount

try cutting off the recuits on a high level sailor, and you will notice the ability bar go
down.

Recruits dont add to ability, but have 2 very important jobs:

more recuits = you gain experts faster

More experts = your sailor performs ALOT better.

And also, if a critical shot is made agaisnt you (larger size font on the dmg numbers)
your recruits act a 'buffer', protecting your more important experts and vets (if you have
any)

Gaining vets is a gamble.

If you click on your experts when you have more than 10, youll notice you can choose to
make them into vets. Be warned, this only has a approx 10% chance of working. if it
works, you lose 10 experts but gain 10 vets. If it doesnt work, you lose 10 experts, and
gain nothing.

If anyone sees ive missed something out, plz post :)

I'm not sure I understand that. AFAIK I could only buy recruits - not experts or vets.

So, do I fill up my units to max with recruits or don't I? Will gunners fight better at
full strength than lower or is all that matters the actual number of vets and experts?

Max is set by the lvl of ur sailor... Lvl 1 = 60, lvl 2 = 65 etc... Generally, that's the rule
although at high lvl, that's diff...

Well, abilities are affected by recruits, experts and vets.

Yes. Recruits are also in. Try burning your experts on restorer and u'll get like 100 SD
in the end and when u "buy" back the recruits on ur restorer, u can end up getting
102 or 104 SD...