Not to go against the common wisdom but the NACA ducts at the front don't seem to be real NACA ducts. They're just a hole with an airstream redirecting wall.
I don't even think a true NACA duct works here or is even necessary. I'm talking about harnessing the "ram effect" of the air stream to compress air and have it flow faster out of the rear sides, and possibly top, of the windshield to counteract the negative pressure immediately behind the windshield.
The hood is necessary to help gather a large volume of air.
BTW, I found that bending polycarbonate requires some complex techniques. So that's out. I'll see if I can rough something together from something found online.