Yes that was what I was suggesting... although triangle bracing on the lower sill would be good, and please don't take anything I said as criticism of what you are doing, sounds like a great project.
I used Porsche 996 rear hubs and uprights. The brakes are an unusual combination. I used Porsche 928 S4 FRONT rotors & calipers mounted on the 996 hubs. To accomodate the SCTA wheel requiremtns I had the Porsche 130mm bolt circle re-drilled to 5" BC and inserted 5/8" NC threaded studs in the hubs. This way I can use 15" steel racing wheels. Cheap, too. BTW, the SCTA also requires 1"hex steel lug nuts.
Lozenging basically means the square cross section of the side pod becomes a parallelogram. It's not clear to me, but I thought I'd raise the question. If FEA is not available, building a scale model out of balsa wood might give you indications. Edit didn't see the most recent posts, subject covered.Tom, what do you mean by "lozenging"?
at the moment I only see the advantage of the big sidebox in relation to the tank.
The solution with the 45° struts is lighter, but offers hardly any space for a tank, especially if it should be removable.
I once sketched a solution where the tank can be removed to the rear when the cross strut (red) is screwed on.
Pink is the tank, grey are crash elementsView attachment 106231