Bead rolling?

[INTMD8]

Just wondering if you guys have had better luck with certain types of dies vs metal warpage?

I cut out an 18 gauge steel one piece trunk floor for my Cadillac, put quite a few patterns into it with an 1/8 step die and warped the hell out of it.

I was cranking it down rather tight, maybe that is my problem?

Or is everyone pre-stretching with an english wheel? (which I don't have).

I may have just put too many beads into this thing but trying to avoid the next one being a taco as well.