Just had a quick look at the kit last night and roughly (very roughly) put a wheel and tyre up against the Fuselage and it looked like one takes up about two Frames (well two windows anyway which I assume equates to two Frames?).
If so begs the question are the wheels and tyres of the triple the same as on the double?
Would think so but will have to check the size of the existing undercarriage bay in relation to the double and see if there is at least one Frame (if not more) clearance for the double. If not can't see how the triple would fit in an undercarriage bay extended by only one Frame. The Plot thickens ...