The wireframe feels ready. I already got to twist a simplified version in a FEA program.
The frame is supported from the upper rear damper mounting points, and it is twisted from the upper front damper mounting points.
I got a stiffness of 936Nm/deg, when Ron Champion says the ready frame should be 1630-2030Nm/deg. At this point adding panels seems a bit difficult, but hopefully it will get sorted quite easily.