O Oh you opened the can of worms and mentioned copper grease and brakes in the one post.
An FYI - you don't need copper grease on modern brakes. Look at the pistons on the Tiger's brakes. Assuming you have them in the right way there is only a thin circular edge contacting the pad back plate, via the removable shim. The reason for that set up is to avoid pads sticking to pistons. Side benefit is the prevention of squealing brakes.