As I suspected the patch distorted when I folded the lip most of the way over.
Desperate problems call for desperate solutions. I can't really recommend trying for several reasons, even though it worked for me. Reasons to avoid this:
1) I have done very little heat shrinking and have almost no experience.
2) Mapp torch is probably not the best for heating metal.
3) I got lucky but still remember #1 and #2.
My solution was the heat metal where I though it was high/stretched until red and then put a wet rag over the red hot spot.
The shape has almost been restored. A little more work and the patch should be ready to weld in.
You can see that I have the lip mostly folded over here.
Although still far from complete, it's beginning to look like I may be able to repair the trunk lid. I was not sure I had sufficient skills to make a patch this large and complex. While I am aware of many techniques for metal fabrication, I lack experience for making something this complex.
BTW if you are wondering what I going to do with the relief cuts, I plan to stick a sheet of copper under the cuts and weld them solid.