For RN, specifically using Hero crew:

Gunners, only consider reload gunners or you are wasting the Hero stats. You will only top out RN reload at relatively high levels, but you will have topped accuracy by ability before level 75. My Blitz 11/11 reloads are at about 85% accuracy at level 60. Putting a 14 base as gunner would have been a complete waste.

If you are going to use as RN AA gunners thay need leaving as armourment until they are near 100 or they will not come close to reload cap.

RN has good secondary Rep and Restore, but mediocre Engines. Hence, RN Heros would be brilliant. The restore cap is easy to hit with them (even on SS) and repair has a very high level before you reach the cap. Overheat SPEED will cap quite early but duration will continue to rise. Hence, good use for Hero is engineer.

Repair would be good, but you are wasting an Engineer base of 14 as engineer stats do not work unless classed as such.

Restore is a complete waste for any crew in RN

Pilot would help with 14 base in Air, Fighter or Bomb with help towards Restore and repair that most pilots would not otherwise provide.

So, basically I would class RN Heros as Engineers first choice, pilots second.

You repair cap with an RN crew by the large amounts of repair that can potentially be provided by the 8 RN Engis that would be a part of your crew, as well as using AA gunners with a high base repair, because in order to access the best RN AA guns and have good reload ability most players delay class their AA gunners as armament sailors until they are closer to the reload cap(Which has the secondary effect of providing more repair) before classing into the AA gunner line to access the A guns and PomPoms.

A lvl 120 Boosted Hero Engineer, classed on time, with 200 vets and full experts has a repair ability of around 2.6m, meaning that if you managed to obtain 8 of these then they alone would contribute 26m repair ability. You would need to find a way to earn another 9m repair from Main and AA gunners, the BO and the scout, you would probably rely on boosting the engi vets much higher than 200.

I have 8 of following engie:

I have 2 of following gunner:

If you do the math, you'll find the Repair Cap is reached by the 10 sailros alone.

To be honest, I do not recommend you go spend your Hero Sailor on late-classed engies, (although they will be excellent, and it's totally up to you).

If I were you, I'd use Hero Sailor as:

Late-classed Fighter

Late-classed Sonarman

So basically you guys recommend using Heroes for support slots intead of gunners (Which was my original plan).

I might just get 2 Elites for gunners and dump a couple heroes into engies then, at what level do you recommend me to class them?

One las question arent fighters and sonarman for CV's?