someone posted on my last thread that about drill and tapping the tang, I over thought the last post greatly.
plan and simple
drill and tap and 1/4 nut to take an 10/32 screw/rod, i soldered it into place. removed the back tang screw, put it into that hole (nice and tight) crud peep sight.

side note, found with the gmb, with a little filing to the screw mount holes and a little bit of crafting foam , an 10/22 base will fit good for a long eye re-leaf scope or a red dot scope.