I took your approach and took some movies of the back sides of the front and Rear Passenger side tires. The Front and Rear have about the same clearances. Little over .80" upper clearance to the lower spring plate and about a 1.0"+ .5" clearance to the shock surface. Based on the mounted 245/35-19 at 25.8" front and the 255/35-19 rear 26.0" tires.
Using the following:
[Bridgestone Protensa RE-71S measurements.]
[
https://tiresize.com/wheel-offset-calculator/]
Based on [19" APEX SM-10 Staggered Wheel Set - performance wheel. 19x9 ET25/19x10 ET38]
The Diameter [less than 1%] rule matches any squared set up to the 285/35-19 [width limit front]. Plus, the staggered 265/35-19 front to the 305/30-19 on the rear. All square pairs are the exact same diameter, as is the staggered pair. The 275+ sizes could be spaced the 70 mm [.375"] to assure width clearance while remaining in the "Street" category for SCCA Solo Rules.
