In photo #1 I'm doing a test bend. I move back and forth from end to end of the brake, tightening the nuts by 1-1/2 turns each time.
In photo #2 I have two lines drawn at 15/16" each, off the bend centerline of the skin. These two lines correspond to the width of the brake's notch. So I just aligned the two outside lines at both ends of the brake, then put the rods in place and set the 2x8 over the rods (photo #3).
Then it was time to start turning the nuts... More photos on the next page.