Something needs to be repeated here, your wheels ARE NOT HUBCENTRIC! Period.

The 2.125" hole is for mounting the cap that finishes the look, it has NOTHING to do with anything else.

You are correct, the fins are holding the wheel away from the face and causing your problems.

You could grind off the fins in the area where they hit the wheel. Either use a handheld right angle grinder and spin the drum as you grind off the fins, or else put the drums in a lathe and machine off the fins so the wheel fits flat against the drum. Or, change to non-finned drums. Or, use a spacer.

These wheels are really cool, but one has to understand they are for appearance, not really for high performance.

R.