Both braces are complete now. The black circles are traced from the holes in the original cowl. The red circles are from measurements taken from the original pieces. They aren't quite the same. I am going to wait to drill the holes until I can be a little bit more certain where they go.
The repair panels were on the front porch when I got home tonight. I decided to put the braces and panels in at the same time so I could be sure everything fits. I checked to see how high the pits were. The cut will be made just above the worst of the pitting.
With the old cut away, the remainder is pretty solid. Now I just have to fit and cut the replacement panel. Cutting, welding, grinding.