69 firebird 1/4 panel seam issue

[jlwdvm]

Uncovering some "issues" with my current project. Previous owner replaced the quarters, but the seam is in the middle instead of up near the roof where the factory would have leaded it in. THere is a low spot across the seam that was filled in with filler over 3/16" thick on each side. I am in the process of stripping the epoxy primer off the car and will prep and reprimer since I don't trust what is undernieth. What should a first time body man do?