Howdy Jack:
Thank you for the kind words. Your opinion means a lot to a guy who doodled Pfledge inspired canards on the margins of his papers as a kid.
I need to check my GCR and science the hoop out a little more before I can answer all your questions. I think if I go chrome-moly, I may be able to use a smaller dia. The hoop and brace will both bolt in. If I go with a hoop that only covers the driver's side, I only need one brace. That is a huge help for driver ingress & egress, as well as the overall look. I am a little concerned that any hoop big enough to work will look silly. I am seriously considering fabricating molding a hunker down seat from resin & beads that I would use for racing only. Then I could make the hoop follow the LeMans fairing.
The strongest point to attach is a steel panel ahead of the rear wheel on the side of the car. That means that the legs won't be straight, or will need a knee on one side. In the middle of the car, the hoop will go straight down to a plate on the top of the tunnel.
The single down tube will start near the top of the hoop, and traverse the passenger compartment to the outside bottom of the foot well.
I wonder if I would be allowed to use some type of Dutchman's clamp on the hoop so that there isn't a tab waiting to bash my skull in when the brace is not installed?
Regards and more soon,
Mark, builder of "Invincible II(a?)"