For Stock Steel Wheels - Shave Wilwood D52 Calipers?

[ShortCST]

I located a couple of clean 4 nub 6 lug 15" steel wheels with 4.0" inch backspacing. Got 'em powder coated. Then I bought the Wilwood Dual 2.0" Piston D52 caliper disc conversion to replace my original 1968 C10 front drum setup.

Just placing the rotors and calipers into the wheels laying on the garage floor, it is clear that the calipers aren't clearing the wheels.

Is it easy enough to file down the outside edge of the aluminum calipers? Does a lot of material need to be removed. I'm not afraid to paint over some exposed aluminum.

I'd really rather not use spacers, if it can be avoided. If it can't be avoided, could someone please let me know what thickness I need? I'd very much appreciate someone who's done this giving me some insight.

Thank you.