[Blas]

D-CEL,
A very unique solution. And the execution look to be very well done. I would like to suggest that the nut and bolt for the rear brace should be reversed to expose the back of your head to the smallest projection possible in the event of a collision. I take it you must me of shorter statute so the top of the bar is not a concern for you head? Remember, in the event of a rear end collision, your body will move backwards and up I believe. But a very well executed job overall.
FYI: When I made my hoop pad, I wanted something to absorb some of the impact in the event of a collision. My original design utilized a aluminum back plate with a foam cover. After much deliberation, I decided on plywood for the back plate, covered with a closed cell foam pad and an covering to match my seats. I wanted the finished pad to extend well beyond the eyelets for the shoulder harness so I set it inside the hoop to make it thicker. The theory being the plywood woud absorb some impact and probably crack in half... which is a good thing. The closed cell foam would also absorb some impact. Lets hope I never need to test the design.