After admitting I misunderstood how wheel widths should be measured, I finally scratched together enough money to have my tires removed from the rear wheels and the wheels shipped all the way to Prather, CA where Rally America will - again - cut the center out of my wheels and weld them back in a slightly different position.

*sigh*

They are moving them 0.75", leaving me just 0.25" gap between the wheel and the suspension. Fingers crossed...