"Any tricks?"
Mine was rolled under as most are. Hammer, dolly and a 2x4 is what I used to get it close. Then finished it off with filler. But most of the filler was sanded away, so thickness wasn't an issue.
For someone as myself who isn't in the auto body refinishing business, just took time, and many roll away, and come back later breaks...
Tim (0lds45512) would be the guy to help you out. He's the forums expert body guru.