I know with a screw on can, you do not use any crush washers but when you attached a QD mount do you use a crush washer? Also, does it hurt to use spacers to time the mount?
I usually use shims but not always. Torque to spec using the forward control design muzzle device tool. I’ve never used any type of thread locker but a lot of people do.
If it’s a flash hider type, you don’t need to time it with shims at all. Just proper amount of torque and some threadlocker for insurance if you’re so inclined