Looks like good work for a slapper, at least to start. Do you have any slappers?
David
Can't you cut the large flat outer and then bend a strip of flat alloy all the way round, Then tig together, Maybe in a few sections, It would be a bit Square looking, But I think it would work.
Cheers Bill.
Your other option is to make duplicates of the wood forms that you already have. Make them smaller by the radius you have on your current wood bucks. Trim your metal to shape but a little larger than the depth of you buck. Clamp the metal between the wood pieces and using a caulking tool and drive the metal over your buck. Essentially you are doing the work of a draw die. The wrinkles that you're worried about occurring from shrinking will end up on in the excess that you will trim off.
Steven