probably just adding that info to the loadout information displayed for selected weapons in the loadout screen. this data can be added to the +Description: tag. ive done that before. your kinda limited to about 4 lines of text though. this text can be whatever the **** you want it to be, and can be assigned on a weapon by weapon basis. you cant really say how much ammo a particular weapon will actually have when equipped to a certain bank, but you can standardize your bank sizes. would actually be cool if you could insert text codes in description text, which are replaced with various informations, like how many rounds you get in the current bank with he currently applied weapon.
perhaps also include a second description field for equipped weapons and use the stock description as the one to use with available weapons (but not currently equipped). like when you click on a weapon in the selection you get a general weapon description, but if you click on a weapon equiped to a certain bank, you get a description detailing how that weapon works with that bank (such as how many rounds or if the bank permits autoaim). id actually at some point like to see a customizable loadout screen. doing it with scripting you would need an indexer to the team loadout and another one to gain access to the wing slots. this would allow you to set the loadout through scripting. though a non-scripted solution for the masses is probably preferable. i want to see things like display of external weapons and weapon selection for turrets and countermeasures (and potentially tertiaries). this of course would probably be pending an overhaul of the ui system.