Mine are a bit more than that, and no, I do not have a rotten frame to make the body sag in the middle. I noticed that when I cut out my floorboards that there were body shims on one side but not the other, all original. Like the TR2-3, the TR6 was never a perfect fit on the frame and shims were needed to "correct" body alignment. I have considered lifting my body and reshimming but don't want the hassle. But your original guesstimate is pretty darn close to ideal, the greater distance in the front needed for hinging. I remember when my paint guy reinstalled my doors, he closed the gap on the front too much and bent the sheet metal.