Wouldn't just masking friction surface work faster and better? To break in pads, light use a bit to kind grind imperfections off, then work up to hard as you can and not crash, yet never let pad stop tire completely. Dozen plus times maybe to heat them as hot as you can ever expect them to get in real use, unless racing, which is how they should run em in too.
I painted my factory but holey rotor gold inside all the bizzillion holes, but wiped excess off dry rag then light solvent rag, then later light sanding to new metal and then straight to new pads "burn in".