When you say "If the mounting holes are non plated you can place a small non plated hole in the center ".....do you mean "If the mounting holes are non plated you can place a small plated hole in the center"? Or do you really mean place a non-plated hole inside a non-plated hole?

On a two layer board design how can I make a circular keep-out area in a ground plane layer around a mounting through hole? The board will be mounted with standoffs and I wish to have clearance around the hole for the standoff & screw head to contact without digging into the plane layer. I wish to k...