Very good points Henry, a wavy large panel is a lot more than just running a shrinking disc over it. I haven't a bunch of experience with the shrinking disc, I have one, have done some pretty amazing things with it, I am VERY impressed with what you can do. But I would be VERY cautious about running it over a hood.
There are so many things that could be at play here as you pointed out so well.
swvalcon, here is a "Basics of Basics" on large flat panels, there are a number of other things to think about before hitting it with heat as Henry points out, check it out. Large Panel Repair - Autobodystore
Not saying that anyone is wrong, Pugsy knows more about metal fabbing I could dream of. But just from a repairers point of view, with average skills, that is how I am seeing it. Read the basics and there may be something there for you as well.