Remember that your biggest problem with wheel fitment will not be diameter. The fixed calipers with multiple pistons stick way out past the wheel mounting surface of the hub. In fact, the calipers on my hot rod stuck out farther than the lug studs.
The back of the wheel has to poke in far enough to reach the hub while the spokes sweep outwards all the way to the rim of the wheel.

My Boyd Coddington Smoothie II wheels had to be cast with an extra 1-1/2" thick pad on the mounting surface. The centers were then welded into the rim and extra 1-1/2" farther out to make the backspacing work. That didn't give me much clearance but it worked.