Based on what I see in the rain on I-5, what pictures don't show is a forward rolling bale of air that pushes out normal to the wheel face. The air curtain's energy sorta slices that off, so I don't think the lateral placing is critical, but a converging duct is.
One thing that's changed since Permalink #93 is I've pranged the new front bumper, so now I can drill holes in it.
