Help with Rear Patch Panel Fleetside 66

[msg]

Anyone have any tips on how to handle this?
My 66 has been needing the passenger side repaired and I ended up buying a patch panel and a few things threw me.

The top flange of the patch panel where it meets the seam, I cant figure on how to start the cuts. The patch panel has a little extra flange/lip that I didnt know if its supposed to be cut off? Or am I supposed to tuck it under the seam somehow?

Also the panel is longer than I realized, and rustier straight out of the box
I am not sure if I can use this panel or not.



I think maybe I should cut just the section I need to make the repair, so I took some pics of where the panel is distorted.





All that mess on the distorted area was me trying all kinds of things to get the panel straightened out. Stud welder and slide hammer. Heat shrink disc. In the end there was so much oil canning and rusted holes that I figured get a patch panel and redo it. Now I cant figure on what the best approach.

Any help is appreciated.