where's the interference? the face of the caliper to the back of the spokes? or the diameter of the caliper hitting the diameter of the rim?

If it's diameter based, maybe you can do some light clearancing of the caliper to get it to clear? or see how thick the rims are and try to turn them on a lathe to provide more clearance?

or a combination of both...


if it's from the face of the rotor to the backside of the wheel face, a simple spacer will be fine. once the wheel is torqued down, the loads on the wheel studs, wheel bearings, etc. is no different than a different wheel with a shallower offset.