Russ, my apologies for using the wrong name.
I didn't realize that mount used a spacer block, but it makes sense. Your custom stainless block is very creative and looks like very nice work. Thanks for posting the photos. If you like the extra weight, you'd probably love the 2206 and in particular the 2206TGT target variant. Drilled and tapped for optics, custom grips, Millet adj target sights, and all stainless construction.
One more question on the b-square mount. It appears to be high enough that you can field strip it without removing the mount. Is that correct? IMO that is a superior mount to the one that replaces one of the grips. (aimtech?)