OK Kids... a lot of view and discussion since midnight.... Look back at the original pictures if necessary... The rectangle that forms the frame is and will be 24 x 16 inches... the old roll hoop was 9 inches above the top of the top rail. To accommodate the growth of helmets I planned 9.5 inches... it actually became 9 5/8ish+, when I coped it in so I will deal with all that extra frontal area with HP increases in the engines...
The flat on the sides of the tunnel are theoretically down force with the rake of the car about 3 inches... I'm not an aero guy, but I'm also not a guy that argues with the success of our original design.
I wear a size 13.... it will not fit between the bottom and top rail... that's about 12.75 inches for the math challenged....
Back to the front bar... to the top rail would would be nice... and not totally out of the question. I need to find a 5.5 x 1.625 JD2 die set to borrow. I haven't checked yet, but it may be possible to make the bend to the rail or very close to the rail to a vertical. The goal is to try to keep as much of the front bar out of the limited driver space as possible.
Discussion is ongoing... more to follow