So here is the beginning of this build, the basic frame.
No laminated parts, however there are separate inside and outside pieces which doubles thickness for strength.
location of the vertical cross pieces is well marked but the top and bottom plates for each are not and the drawings are too vague to help. Centering these plates seems to be the correct move for parts 4, 5, and 6. Part 3 appears to be a C channel shape.
The rear storage(?) bin is a tight fit. I had to trim the top and bottom plates of the frame and cross members to get it to fit. The bin still slid in snuggly and is not glued.
Supposedly the center box is the fuel tank. The front seats mount on top of it later on
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greg