Well, six months later ... the Beacon Hill has been calling out, and today I got back to work.
I went with my initial thought, to use string to form the standing seams in the copper roof panels. I made templates with graph paper, the easier to space the seams and keep them straight, and used the all-purpose white string in the kitchen drawer. They're glued with Aileen's tacky glue.
I placed the template on the sticky side of the copper sheet and gently rubbed it out smooth with my fingers. I then turned it over, trimmed away the excess copper, and used a burnishing tool to smooth out the wrinkles and enhance the "seams". I'm pleased with the result.
In the photo below, the panel is not pushed in all the way. I'm going to keep the panels loose until I figure out how they will be aged. Some of the aging may be easier to do it I can lay them flat. The white boards at the top will be painted black.
The next step is aging the copper. No way can it stay this shiny! I'm open to suggestions as to what methods to try.