No magic here. The twist goes extremely quick and is very easy to do. Looking at other blogs, I used a piece of 2x4 that I cut out the shape of the angle out of the wood. It was about 2' long and made the bend very easy.
First I verified that I was 0deg before the twist.
I used the 2x4 to twist the angle. I must admit I checked about a hundred times to make sure that I was twisting the right way, the top of the angle bends in, and the bottom bends out. It only takes a few mins to get the 17deg bend.
So glad to be finished with the longerons. They got stored up in the garage for installation later.