Already done, sort of. Read up: https://www.allfordmustangs.com/forum...ing-shape.html
This is correct. Using the fatter, older style bearing without changing the race to match results in disaster. This did happen to someone on here, I think I remember reading about it. The techs at my friendly dealership inform me as we speak that they've seen this happen several times and it usually destroys the housing.
On this (round #5) of differential set up, I will be using all Ford OE bearings including the "correct" skinnier inner pinion bearing just for the hell of it.
I won't have my car back (still) for a few more days as they had to order out a new clutch and flywheel since I managed to destroy the stupid spring that holds the dual mass together.