Whoa! I know exactly what you mean about the measurement differences. Doing the Topsters we've run across some pretty strange measurement changes in 32 roadster bodies, and I mean changes that I just can't understand why they'd change them! Kilbourne bodies, as an example, are about 2" narrower than most others including original steel ones, and they've got a couple of other diferences that make them just enough different to undoubtedly cause an owner grief for sure. We have a measurement sheet that I send to each customer and they compare the measurements on their body to those off an original one (or my Wescott one that's the same) and we can modify their frame to fit THEIR body. That said the only measurement change I can "kinda" understand is the 2" stretched thing in the cockpit, but then again being very "traditional" in my ideas on roadsters I prefer the original size even tho I'm 6' 2" !
Again on changes tho, one of the main reasons I went with a Flatlanders - New Age body was because they have the drip rails. To me a 5 window HAS to have drip rails!