That looks pretty good to me. I notice that in addition to eliminating the death cap from the common terminal of the GND/REV switch you would also eliminate the .047 cap across the terminals of the ON/OFF switch. It's been a long time, I think I might have left that one in place thinking it's purpose is to ease the burden on the switch contacts at turn-on and minimize pitting. The power switch is pretty light duty and a bear to replace. If the GND/REV switch shorts it's going to light up the chassis, but if the power switch cap shorts it seems the worst that would happen would be that the amp never turns off. Anyhow, what you have sketched out should work.