need some advice...70 Duster hood

Hmmm. I've never thought of removing that material for this very reason. So I guess I would maybe try putting the hood upside down with just the 4 corners being supported by saw horses or whatever. Make sure they are all the same height so you don't put a twist in it. Then I would turn the lights off and lay a flashlight underneath the hood so it shines flat across the surface. I would inspect for any depressions, etc using the light to detect imperfections. I'm thinking you could then put cardboard shims in various places, again checking for any distortions using the light trick. Once it looks good, I would replace the goop...which I'm not sure exactly what it is as I have never replace it. If you havn't found it yet, I would look to 3M or SEM for a possible match. Good luck.