Explanation about what are the best bases for sailors:
Gunners.
Most of people think accuracy is more important than reload. That's not truth. In general the most important stat for the gunners is the reload.
With BVE gunners when you reach certain lvl (around 70-90) the accuracy of your gunners just depends on lvl because accuracy cap is level-dependant.
On the other hand the reload cap is an "absolute" cap, it is around 2.5M in true ability (TA= (Nexperts + 4*Nvets)*(Displayed ability). And you reach it in general in lvl 90 or higher.
For more details, read Adalbert guides.
We also have to mention in WaW mode there is no reload cap at all.
So, for unespecialized nations in acc/rld (all except us/uk) the best choice is gunners with good rld stat. Let's say elite rld or 10acc/12rld.
For UK/US cases there could be other point of view, but i would recommend too good base rld gunners and go all upgrades on rld.
KM AAs/IJN DP gunners.
Also the stat important for them is the reload, not accuracy or (my god) the AAW stat. We have to mention for leveling DP gunners you have to keep them as arm sailors as much lvl as possible because they gain more reload that way.
Repairers.
Obviously the best stat would be in repair. People also try to get a decent base on restorer too for helping a bit with SD in mid levels, but i would preffer always a elite repair than a 12rep/11rest.
Restorers.
Of course elite restorers. The same way people try to get also a good repair base, but i would always preffer an elite restorer than a 11rep/12rest.
Engineers.
Well, the 3 stats works in engineers. Rep/rest/eng. Depending on for what you want the engy best base is elite engineer or 11rep/12eng. There is not an absolute truth about it.
Scouts.
+12 aircraft. Aircraft is the only stat that matter about scouts for defense. Many people choose them elite fighter, i don't understand why. Aircraft stat determinates both the attack and the defense of a plane. If i'm wrong someone correct me please. On the other hand people also looks for a decent repair base apart from the 12 on aircraft.
Fighters
Fighter ability (along with the plane stats and the skill of the player) determinates the attack/defense of your fighters. So, elite fighter. Also people use to make them only the first classing for having more crew at lvl 120 and the possibility of putting more vets on them. For more details read adalbert guides.
Bombers. (DBs and TBs)
Bombers ability determinates the attack/defense of your bomber planes. So, go elite bomber. Anyways Bombers users don't pay much attention to the bases since if some fighters caught you they will you no matter u have elite bombers or +10 ones.
Torpers.
Torpedo stat is the only one that matters for the reload time of the torps. Reload stat is for guns and there are still some people around that are not sure about it. Also, rld cap for torps is around 1M true ability, that means you can scrap recruits from torpers at high lvl and save some weight on your SS. So, elite torp are the best ones.
Sonarman.
Well, many points of view here. Some people use to powerlevel them as supports sailors as much as possible for gaining more rep/rest, other people use to class them on time for getting more sonar ability.
So, if you are looking for rep/rest ability 14pot/11rep/11rest and powerlevel as supports would be good.
If you are looking for sonar ability elite sonar and classing on time would be good.
Planesman.
Again the same, like in sonarman we could argue what is the best base or not depending if you are looking for rep/rest ability or planesman ability.
Seaman.
You want a seaman for better fps? Choose elite fp seaman. You want a seman that helps with repair ability. Choose elite repairer seaman. The number of vets doesn't affect a seaman at all, tested, all that matters is the base in the stat you want to improve. Anyways the seaman gives you a very small boost and i personally don't recommend it at for nothing, not even CVs.
Bridge Operator.
Potential ability determinates the length of the guidelines, so if you want to have proper guidelines sooner, choose elite potential sailor. If the BO is for a CV choose elite rep or elite restorer.