MANY THANKS! Seriously, I really appreciate the guidance. It was not easy or fun, but now I’m done. Used a dremel to cut notches into the plate (no room for anything else!). Chisled and chiseled. On the third rotation, the captive nut became “uncaptive” as in no longer welded to the frame. So I drilled a pilot hole to ensure the right spot to drill on the inside, then drilled a 1” access hole through the floor. Used an old broken long drill bit through the pilot hole of the plate and frame to lock the plate in place while undoing the nut with the impact wrench. The access hole, although annoying, validates using the $9 aftermarket bump stop/helper with a nylon lock nut versus the $60 OEM part. In reality, once I finish the moderate restoration, this will be a garage kept, good season, nice weather, weekend only car that won’t get more than a total of 1,000 miles during the next 60 or so years of my life... I’m 48 now, so yes, I’m definitely an optomist.