grandagon N lenses f4.5 75mm vs 90mm??

Which of these two lenses performs better? I understand from Rodenstock's MTF c urves that the f4.5 versions perform better than the f6.8 versions. The 75mm f4 .5 is considerably lighter than the 90mm f4.5 and their MTF curves are virtually identical. Does anyone have any first hand experience with these two lenses?

I have shot the 75mm f/4.5 and both its sharpness and color are wonderful. I have also used the 90 f/6.8 and been more than satisfied with it as well. The 90 f/4.5 is VERY large and heavy. If you are shooting 4x5, the MTF difference between the f/6.8 and f/4.5 is insignificant at real shooting apertures. In fact, the f/6.8 has a slightly "flatter" curve, without the dip that occurs in the f/4.5 about 2/3 of the way out in the field. Your real decision is whether you like a 90 or 75mm more. I find 75mm very wide and harder to compose, but then you can always crop.