New to the forum...not too sure if many 1st Gen gurus still lurk but I am hoping!
So I brought my 1980 Accord in to get the clutch surface machined and they did both the mating surface and the pressure plate mounting surface. The problem is that I am pretty sure they ground the pressure plate mounting surface too much (it was a bone head Napa employee) and I need to know what the difference is supposed to be between those two heights; friction face thickness vs pressure plate mating surface.

Right now I have less than a single mm which certainly seems significantly less than what it was when I brought it in.