I bet that guys car shows shadows of a line on a hot day where he glued his quarters on... My Dad tried that glue once before (on a dark coloured car) and he tac welded it in a few spots too and after bodywork and paint it looked perfect, but on a hot day you could see a line where it was glued and he never used it again. He used Fuser glue which is high end stuff too. I wouldn't ever use that glue on a rocker unless it's used for sealing a seam (like a cowl) and spot welding like the factory did (you can get stuff that you can weld with)