Probably a mix of engineers and repairs would work perfectly fine, havent played NM 45 yet

If you don't have AA gunners/PHH gunners then put your repairs/restorer on your T slots. Engies won't work on your T slots. If you are using T slot guns, then my recommended setup is 3 engies/2reps and a scout. If you don't have T slot guns then I recommend 4 engies, 3 reps (2 on T slots) and a scout.

5eng 1 scout

You need engineers direly later on, so get 5 engys, 1 scout. Then have 2 reps in your t slots. later you'll need to get 2 more reps and a seaman

in my opinion using PHH/AA guns its a waste of space...

first of all if you use T slots you will loose 1 or 2 knots and besides you will have to rotate the same ammount of sailors in less space...

i have myself 4 reps and 4 engy, 1 rest and 1 scout (besides 4 gunners, 2 main and 2 sec.) and i have been using 3 engys 1 scout and 2 reps in support slots, and 1rep and 1 rest in T slots...

this i think its a nice balanced config that will give u good SD (with the rest.) good rep. (3 reps) and good speed and OH (3 engies) u just have to rotate 1 engy and 1 rep...

and your secondary gunners will be able to lvl up above CL & CA when you want to powerlvl some random crew...