I'd recommend that you look at as many World Solar Challenge competitor cars as you can stand,and see if something strikes you and looks like you could mimic the fabrication.They're all going to be low drag,whether wing,or half-body in origin.
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If you were going to try to use the VW chassis,you might be able to graft your sectioned truck fairing for the nose.It would save a lot in fabrication time.
This 2012 Bochum University SolarWorld GT is a nice and easy to live with 2-door coupe.You just walk up to it,open the door,get in and go;without requiring a 'crew' to get in and out.It's Cd 0.137.pretty sweet.
If you extend and soften the rear contour you could see Cd 0.10,like the 2013 Cambridge University's Eco Racer,CUER
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For 'wing' type side-by-sides,you should find a bunch of examples from past WSC competitions.They would be easier to fabricate and they'd have less frontal area.
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Plex or Lexan bubble windscreens may not pass legal requirement.You need to know.
This 'VORTEX',from the 1980s used flat laminated safety glass for its windscreen.It might be a 'default' design if push came to shove.
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Fun project!!!!!!!!!!!!!!!!!