Just to throw more wood on the fire... Tire inflation is going to make a difference. I just measured my PUP Y @ 45 psi cold: Front left - 29 7/8", front right -29 3/4", Rear L & R - 30.5"
EDITED TO ADD: I also just measured tire height. Again, 45 PSI cold. (The car has been in a 50F garage all night.) Front - 27 3/4", Rear - 28 1/8". That means actual tire diameter varies front to rear by only 3/8" and not .6" (Assuming equal bottom side compression.) We really need to measure circumference of the PUP tires to find the actual diameters. Anyone have some chalk? Mark straight down on your tire and on the ground at that point, pull forward until the chalk line is straight down again. Mark the ground there. Measure between the lines on the ground; that is your circumference. Actual diameter can be calculated from that.
Seems like a lot, but outfits like Mountain Pass Performance could use that information to start getting suspension components figured out for the Y. I know MPP has a Y on order, but given the current crisis it might be a while before they get one.