I opted to use much finer papers for the job, starting with 600, then 1200 and finishing with 2400. I had two, small dimples at either end of the ABS comb, but felt there was sufficient material surrounding them that I didn't need to go down to bedrock.
I recorded a few scales preoperation, and post. The difference was easily heard, even by a newbie like me.
Adding the power plugs, or plug ins in the upper octave (now only in holes 10, 11 &12) has allowed me to play without blowing my denture across the room. My bride is very happy about that.