Drilled the hole in the back of the receiver. I also installed my own overtravel screw in the trigger guard. Had to drill a hole for that one also. Not so long ago you had to drill holes in the top or side of the receivers if you wanted to mount a scope. Didn't hurt the function of the guns at all.
I guess I just use what works for me. Advice is a wonderful thing, you can use it or ignore it if you like.
Bubba aka Joe