It's also much easier if you plan to have a BB6 and CV6 of the same nation, as you
can skip on levelling up some sailors.

A BB6 has 14 slots, while a CV6 has 12. So if they were of different nations, you
would need to level 26 sailors. But sticking with the same nation, you probably need
between 20 to 22.

Let's break down the necessities.

For a decent crew BB6, you generally need 1 BO, 2 main gunners, 1 scout and any
combination of 8 support sailors (e.g. 5 eng/3 rep). 12 sailors in total, which leaves 2
slots empty.

For the CV6, supposing you go for 7 pilots, and add to that 1 BO and 2 main
gunners, that makes 10 sailors in total with 2 slots empty. But remember, you
already have a pair of main gunners from your BB6 crew so you can pull that over.
For the remaining 2 slots, you could fill it with an engineers, once again from your
BB6 crew.

Now, remember you still had 2 slots empty on your BB6? Just pull over 2 pilots from
the CV6 crew, put them on the T slots, and you're good to go. Heck, you could even
skimp and go with 7 support sailors, and pull over 3 pilots instead.

So in the end, all you need is basically these:
2 BOs
2 main gunners
1 scout
7 or 8 supports
7 or 8 pilots

Around 20 sailors. Simply interchange them on your BB6/CV6 to fill up the empty
slots. I've ditched the AA gunners for I never felt them to be worth wasting two
slots on.

Yes they're helpful, but not the be-all-end-all to be successful, especially in the
chaotic GB environment, that some would make it seem. I would rather use those
slots to level other stuff.

Of course, this short cut setup means you won't be the best equipped ship out there.
But going back to the GB environment, best equipped often counts for nothing, as
lots of other factors, e.g. competent CVs, subs, dumb flags, etc, help decide the
outcome.

Nonetheless, if you have good situational awareness and are able to recognize
opportunities and pounce on them quickly, this setup is more than enough to reap
you excellent EXP returns.

vets and experts help in your gunners also :) don't forget that, and you can't enter a gb
anyway if you have guns below 11" with a bb/bc

You need to stick to the main guns, otherwise you are basically a support ship
taking up a battleship slot on your team

Ur the best thx.

BB Guns will always have a slow reload and if we talk only about the guns... as the
gun level grows, also does the reload time.

You should always keep your gunners at a higher level than your BO, this will help
you when you get your different BBs as your gunners will be able to use the best
guns for that ship. However, consider that at lower levels, your accuracy will always
be bad until your sailors reach the ACC cap.

Also, consider that for a BB6 you will need 14 sailors:
1 BO
2 Main Gunners
2 AA Gunners
8 Supports (usually 4Reps/4Engys but depends on the nation and base)
1 Scout

If you don't have all those sailors already, then start a New BO and level up the
sailors you are missing. With this new BO, use the same gunners you are using
now... that will help you get them to a higher lvl than your main BO.

*Edit: thanks masc, I forgot the most important part... Always use the main guns for
a BB, you get more range and more fire power. If you don't use them, might as well
use a CL or CA instead.