Most of the info on wheel/tires in free air are for road racing tires, short, wide and with sharp corners, the only info I have seen on narrow tires is for the bike tires that are ran on solar racers. The numbers that I used to get the 200 hp/wheel number were 5 inchs wide, 30 inch dia. and a Cd of .4, using those numbers give you about 180 hp at 400 mph. The .4 Cd was a WAG. What you really need to do is to make sure that there is a minimum amount of disturbance as the air goes around the tire, and I would guess the fronts to be very important because if they develop some big turbulance that could have an impact on the air going to the rear tires. My plan is to have a non rotating disc on both the inside and outside of the fronts along with an aero cover over the steering arm and axle end and spindle and of course have all of this flaired together and the axle to be an air foil shape.
Here is a rule question regarding using what the F1 guys call "barg boards" which are really turning vanes. Could a person use a vertically mounted guide that would be mounted on the axle, next to the wheel/tire that would extend to the rear of the tire and turn the air such that it would be turned into the low pressure area behind the tire, and I would assume that no part of this "guide vane" would be past the inside vertical plane of the tire.
Rex
Sum, I should be there late Friday morning, staying the night in Winnemucca, looking forward to seeing you.