A short update: I milled in some of the bottom metal inletting to reduce the workload. Around each screw hole is a counter bore machined to the final floor depth so I will know when to stop. (these are the same as the steps on the brass receiver pins) The metal from where it is now to where it needs to sink to is about 3/8", so now begins the near endless cycles of inletting. Blacken the metal, try fit, remove metal, scrape away the black impressions. smile