Any gaps in the CPO are unavoidable, especially after some time goes by. My joysticks are mounted from underneath but my trackball plate is recessed on top (with bondo filling in the gaps). I have an adhesive backed CPO graphic over that. I notice at certain angles while looking at it now, that I can see the faint outline of the square trackball plate. It bothered me at first, but I eventually got over it. It's only noticeable if you point it out.
D