Lynn,

Nice job!! Skip the dry ice....

I think the side rippling was due to your technique. As you tightened down the block the leading edge pushed into buldged out area ahead and crimped it in. I've never used frame blocks but I'd suggest either a larger starting gap in the blocks, radiusing the leading edge of the blocks or starting at the widest part of the buldge and wrk out in 2 different directions. Starting in the middle would require several passes.