When a crewman walked into to debriefing, the debriefer didn't ask about the enemy guns, only the ones the crewman was operating, for stat purposes only I would suspect, but I wasn't there, so don't know,, only making a suggestion because I can't remember where I read that or what it was in relation to!
My point is that in AH those aircraft are not enemy aircraft, they are frequently your aircraft. A consistency system needs to take them into account.
2 should be for the most common extra position, probably the tail gun, though top turret might also be considered if we want to count the gun position on things like the B5N, Bf110 and SBD-5 as a top position. 3 needs to be the next most common position and so on. The problem children will be things like the Ju88A-4 with its two side by side guns and the Me410 with its three positions for two guns arrangement. The other question is if we require the positions to be sequential. In other words does an Me410 have to be 2: Left 3: Center 4: Right or should it match the B-17's 2: Top 5: Left waist 6: Right waist? Personally I'd like standardized as much as possible, but then intuitive on the oddballs like the Me410. Having it be 2 3 4 so that I press the 2 key to jump to the position to my left as I am sitting in the gunner's seat, 3 for the center control of both guns and 4 to jump to the position to my right as I am sitting in the gunner's seat would be most intuitive for the Me410.
Gun positions (from memory, so errors may be here, particularly for new planes) that need to be considered at this time:
A-20G: Top/tail (perhaps belly as well when updated)
Ar234B: Tail (hopefully none when updated)
B-17G: Nose, top, belly, right waist, left waist, tail
B-24J: Nose, top, belly, right waist, left waist, tail
B-25C: Nose, top, right waist, left waist
B-25H: Top, right waist, left waist, tail
B-26B: Nose, top, right waist, left waist, tail
B-29: Nose, top, right waist, left waist, tail
B5N2: Top/tail
Bf110C-4b:Top/tail
Bf110G-2: Top/tail
Boston Mk III: Top/tail
D3A1: Top/tail
G4M1: Nose, top, right waist, left waist, tail
He111H: Nose, top, right waist, left waist, front belly, rear belly (perhaps use belly for front belly and tail for rear belly)
Il-2 3M: Top/tail
Ju87D-5: Top/tail
Ju87G-2: Top/tail
Ju88A-4 : Right top, left top, belly
Ki-67: Nose, top, right waist, left waist, tail
Lancaster Mk III: Nose, top, tail
Me410: Top/tail, right waist, left waist (kinda)
SBD-5: Top/tail
TBM-3: Top/tail, belly
Tu-2S: Top, tail, belly