Don, I will have to pass. Family member saw me researching this and explained I have a Holosun 507k waiting to be opened Christmas day. This is a great deal for someone....
Always used a depth micrometer. I would use silicon carbide sandpaper on a square/glass flat surface, then do figure 8's with equal pressure. I had some 90's that had like .015" clearance - I would take off .010" to .012"..
Tracking info PM'ed to you. UPS is typically at my work daily so it should go out today. If by chance they don't stop in today, I will drop it off at a UPS Store. Thanks again.