Did some checking in the hangar. Plenty of craft have up to 7 items and it's possible you can fit more (it wasn't totally cramped).
B-29: even with this behemoth blocking the view it still has 7 options on the left side.
F4us: 7 items in the center
Ju88: 7 items left
Moss6: 6 items left
P38: 7 items center
P47: 7 items center, 6 items left, 4 right
Typh: 7 items left.
So it's quite possible to have at least 7 or 8 (counting 1 for "blank," remember?) on each list in the hangar.
We might even push 9 depending how far back the plane is placed in the hangar view, giving more floor room.
I would really hate to see the 410A/B split up for an arbitrary discrimination (like saying one is a fighter the other is a bomber). It would prevent a lot of useful ground attack combinations for AH purposes.
So, even removing the semi-rare 1000kg single bombload, that puts the bomb bay options at 8 (counting "empty") and the wings options at... well... there's the problem.
You've got to allow the rockets and bombs together, since we have that also on 110G. You'll need to allow the gunpod with either as well, or all 3. Then there's the issue of the DTs.
If you can split the gunpod off by itself, or perhaps the DTs off by themselves.... Maybe separate the belly hardpoints from the outer wings, it's much easier and cuts down on the options.
Big "IF" you can get 4 columns of options in the hangar.
So, trimming the 1000kg bomb (which pains me) and the DTs (rare but useful sometimes in AH! this also pains me) we get them down to 8 items each list.
Main (right column?):
1) 2x MG17 7mm + 2x MG151/20 20mm (plus 2x Mg131 tail guns)
2) 2x MG131 13mm + 2x MG151/20 20mm (plus 2x Mg131 tail guns)
3) 2x MG151/20 20mm (plus 2x Mg131 tail guns)*
(Optional below. I'm still not for these, but Moot raised the point)
4) 2x MG17 7mm + 2x MG151/20 20mm (no tail guns)
5) 2x MG131 13mm + 2x MG151/20 20mm (no tail guns)
6) 2x MG151/20 20mm (no tail guns no MGs)
Wings (center column?):
1) empty
2) WB151 2x MG151/20 20mm gunpod
3) 4x 50kg
4) 4x WGr 21
5) WB151 gunpod + 4x 50kg + 4x WGr 21
6) WB151 gunpod + 2 WGr 21
7) WB151 gunpod + 4x 50kg
8) 4x 50kg + 4x WGr 21
Bomb Bay (left column?):
1) empty
2) 2x MG151/20 20mm tray
3) 4x MG151/20 20mm tray
4) 2x Mk103 30mm tray
5) BK5
6) 8x50kg
7) 2x250kg
8) 2x500kg
Now, adding the 1000kg back only adds 1 entry, but adding the DT back adds: DT, DT+WB151, DT+WGr21, DT+50kg, DT+WB151+50kg, DT+WB151+WGR21, for a total of 6 more items (topping out in the mid teens! far too many for a single column!)
You see the problem with that. If you split off the DT and the WGR21 then you'd only need 3 options (DT, Rkt, none) since so far there's no proof they could be carried in combination.
Then the belly options would just be WB151, 50kg, both, or none. That takes 14 options down to 2 columns of 7 total.
I sent a quick e-mail to HTC to ask a hypothetical about the most any one column can have. Will see what they say.