You could always build Mild and Bitter as well as Flak bait as both were from the same squadron.
Actually, although they were from the same Bombardment Group (the 322nd), "Flak Bait" was from the 499th BS (PN*E), "Mild & Bitter" was a 452nd BS (DR*X) bird... Haven't found any shots of "Mild & Bitter" on a Google Image search yet. Is there something unique about her that you know about A post-mission photo or something? I haven't heard of her until now, other than during the search, I found a 1/72 kit that had its markings as an option.
And how will you improve the waist gun sections?
Dunno, haven't got any pics of that area yet, but I'd imagine that there's a floor, ammo cans, oxygen bottles & hoses, toilet, electrical conduits, etc, and the Putt-Putt (APU) is also in that area, although I'm not sure if that's actually in the tail or waist...