The way Benjie’s bracket extends from the seat makes the plate inevitably hit the rear tire. It was a simple matter of bending the bracket a few degrees to adjust the angle of the plate.

I don’t own a vise. I would like very much to have one but I have priorities for my expenses on this project. I simply used a pair of large vise grips and bent the bracket with my hands.

I think it came out nicely. I have no doubt this will solve the problem. Its unlikely to hit the rear tire anymore.