I don't think I'm the first person to do this. I cut slots in my hoop to fit over the stamped frame. I cut off the excess frame in the back, trimmed the stamped seams on the frame, seam welded back together, and then welded the hoop. I also made some thin bent taco gussets to clean up the transition from stamped frame to tubular hoop. Grind down the weld and sand smooth. I used a Harbor Freight tubing roller to bend the hoop. Most aftermarket hoops are for larger & wider frames (along with half circular cafe seat pans). My Glass-From-The-Past seat pan it a bit pointed at the back, so the hoop isn't a perfect circle, but more like a parabola.