After much fretting about technique, I finally dove in an did my first "free-form" bend of sheet aluminum. There aren't that many parts that require this technique, but they are important ones...like wing skins. Using a 1/2" dowel as a stop to prevent over bending in the crease, I had Joy hold the part while I applied even pressure on the bend line with a 1"x6". The results were encouraging. I'm sending close-ups to Dave Clay and Debo Cox to ask if a re-bend is required. If they say "no" this will be my part. If they say "yes" I happily redo it. It's not that much work, and very little cost. By the way, to get the correct angle, Joy had to kneel on the top of my work table. That's a picture I won't be posting in deference to my lovely wife.