Formed the flanges around the lightening holes of the center brace today.

...then moved on to fitting the right brace. Since I expereinced gouging with the edge rolling tool on the left brace, I decided to try a different approach here, so I made a little bending tool from a piece of oak. It's tapered so it can handle both wider and narrower tabs. The depth of the slot is pretty consistent so all the tabs should be bent at the same position. This worked much better than the edge roller. No gouging whatsoever.