Tommy,
With a 2-piston caliper I don't need to allow the housing of the caliper to float. It will do it automatically with each pad, right? The front/stock caliper on CB750's requires the entire caliper housing to float on that arm 'cause the one pad is fixed. If it's 2-piston the caliper body can be rigidly mounted I believe.

Why do i need an inside spacer? Just outta curiosity.