[gordon]

That top edge looks like you'd have to make it in three sections and join it, which would be no fun. If your sheetmetal guy could make it in two pieces, upright with round section, and flat side with turned edge, that would be less hassle to join?

I think you might have the wrong handle on making imitation rivets too, especially if they are just 1/4" I had the same problem with my K-38 trailer which is almost all rivetted construction.

I ended up making the trailer repairs in sections which were bolted together, then I just bought a small cheap air hammer and adapted hand tooling for rivet set and snap ( E-Bay, cheap ) to take the air hammer end.

After a bit of practice I was able to replace all of the bolts with original rivets.

Gordon