I didn't go back to that crappy hood pad stuff either. The body shop I went to uses a similar but different material to do this. It is less like foam and more like silicone. I had added a cross brace in my hood to push up the middle which had sagged over the years. What we did was use strips of cardboard to get the gap between the brace and sheetmetal. The cardboard went on one side of the brace, then used the silicone on te other. Once it was set, pulled out the cardboard and did the other side. You can see the middle brace was done like a stitch weld. and the shop also did across the back f the hood. And this stuff was also paintable so it blends in real nice.
I have the SEM gun, btw. Got it off ebay cheap, but those SEM and similar 3m products are not cheap. Worth it in my opinion, but no bargain.
Heres my hood...
http://67-72chevytrucks.com/vboard/s...&postcount=495