Well after talking to my brother about this, I decided to take his advice and make the brackets into a two piece affair so that the bends didn't have to be in exactly the right position. I'm also using .032 instead of .040 which is a lot more forgiving. Here's one of the pieces of .032 ready for bending.

Bending in progress. I got four pieces bent, but quit for the day. I had gotten a fleck of aluminum in my eye while using the band saw and it was really bothering me, so I went to an urgent care to get it looked after.