Our friends at NAPA sell a product called “Brake Quiet”.
It is a silicone based, RTV-like product that tolerates high heat and is applied between the brake pad and caliper on disk brakes. Once applied, it cures and essentially glues the pad to the caliper or piston and eliminates brake squeal.
If you really feel that you must chamfer the forward edge of the pad while they bed in, a couple of passes with an angle grinder to take off the forward edge of the pad will do, but try the Brake Quiet, first, and for God’s sake, wear a really good respirator mask and do the work outside. Breathing brake pad dust isn’t good for you.