Mn aa some of best in game in my opinion. I go with 3 reps, 5 engs, 1 scout, 2 gunners for reload (not aa gunners), and bo with 2 R slot gunners

Not sure what ship you're currently in but if you're shooting for bb6, I would do atleast 4 engineers, and atleast 3 reps. I leveled a restorer as well to reach the SD cap faster, SD cap for me came around level 90. I would recommend it as it helps with the rushing ships to pull range with some survivability. Don't worry about having to level an engy or rep to replace him in the end, as the road to bb6 is long. This brings me to your next point about aa being useful; infact it is very useful. MN has very good aa range and a large selection of aa guns, most if not all of their bbs have good aa platforms. I would recommend it as it will really help in leveling.

If you want a balance set up you need 4 engies, 4 reps. AA is useful specially when you are a low lvl, ths will be more useful when lvling ( just what i did). And it depend also if you want speed put more engies, or fast repair rate then more reps. Speed 5 enges atleast, Repair 5 reps. Addition On a BB1 you will be food for gb BB2 you can but food for BB3/4/5 so AA is very useful. Hope this help.

MN AA is very usefull, use it. Besides if you have PHH you can use the gunners for that on ships that don't have good AA T-slots.

Whatever you do, don't make a restorer. MN has +2 restore bonus so all sailors provide more SD than most  other nations sailors. This makes MN restorers even more useless than they are for other nations.

Either 5/3 engi/rep or 4/4 are good support setups to add to the 2 extra gunners.
If you feel like having choices you could do 6/4 in addition to the 2 gunners for AA, but you will definately need a 2nd BO to level all of that.

Thanks to all for your answers.

Sure Iwll go with BO, 2 Main Gunners RLD, 2 AA, 1 Scout ans 5/3 ENG/REP.

Once again thanks. 

as a new player I read this post, it is not easy to find information... yes I search let me rephrase that . CURRENT information about this game and strategies.
I wish one of you RM vets would post guides and have stickies on this part of the forum like the other Nation branches. Thanks would be very helpful for those who are new to game or French line.