Bill,
I have a local guy who does Micro-TIG, very delicate welding under magnification. If the rear spacers are welded you don't have to worry about them moving during the solder job. The wedge between the muzzles is just soldered with Hi-Force so the regulation can be tweaked at any time. I silver soldered a reinforcing bar to the backside of the bottom rib to accept the swivel mounting screws. A lot of smoking, filing and stoning to fit the top rib, it's never an easy job. And you're right, you can make a pretty nice quarter rib out of that Weaver stock by milling away all of the stuff that you don't need.