took 2 days doing it.. all done,, no warp at all.
first day tacked about every 8 inches, few hours later in between ..4 inchs, finished the day at about 2 inch tacks.
2nd day, layed wet towels alongside the seam about an inch away, and just tacked off and on all day, ground down the welds with 4 " cutoff blade, ( way less heat than a grinder or flap disc) all done !! turned out fine, waiting on the maxim urethane to go under hood skin, then ...who knows where I'll be next !