I went to my local sheet metal fabricator. They welded in a single piece of metal which was the thickness of the folded metal cutout. They did it during my lunch hour and they did a great job. I only used minimal bondo. Charge-$65. The local GM paint and body shop wanted $600. They said it would take about 8 hours of labor to do it. That was 4 years ago and it's still looking good. You have to look close to see it was ever done, and that was with me painting just the window frame.