[skunkwerks]

I would not weld that seam until you have re-shrunk the stretched metal from that accident.
You need to get a porta power set from Harbor freight and push from the inside of the trunk caddy corner to the other trunk floor deck lid brace and get that rear portion pushed out more. That is causing most of your problems. I can see it in the shadow of your body line on the Eyebrow detail for the QP. Still pushed in about an inch or so.

That needs to be addressed first.

Then you need to strip the paint in the damaged area and heat, shrink the stretched area using a propane torch or acetylene torch and cool with wet rags. Then use the hammer and dolly to work that area back into shape. Rear corner first. You may still need to porta power the inside while you heat it up and shrink to hold the shape.
Do little dimed sized heated areas along the worst part of the rear crease. You will instantly see the metal tighten back up and the whiskey can affect
disappear.
Just my 2 cents