72 Duster: You can lead a horse to water, but...
It was a futile attempt. I kept burning through while welding since the rust was worse on the inside of the panel than the outside.
Sorry for the blurry pictures!
Although I did finally get the patches in and welded, the panel was wavy and looked bad. It would have taken a bunch of filler to level it all out. I decided to cut the entire panel out and weld in a good used one. BIL was out for another week and is stripping off the primer I sprayed on to cover the bare metal.
He asked me to weld over the trunk key hole since we put in a pull cable to open the trunk.