Good ideas to ground guitars and amps correctly! Copper shield tape or aluminium tape works. It has been suggested back in the 1990's by famous musicians like EVH we eliminate fear of frying by using wireless guitars - also a good idea.

I prefer the noise gate pedal for guitars to kill hum - both Boss and Behringer make good ones. Also if you are so inclined you can purchase a "HUM-X hum eliminator" device by EBTECH for the power cords and surge protectors to get rid of 60 cycle hum. It works good.