Thank you, everyone. The above info and photos (especially the camp trailer corners) are cool. Yes, I agree, the top edge needs something for sure.
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OK, on with the project. Violated my own requirement for aestetics because I couldn't resist testing the concept. Yea, Yea, YKYAEM if .....
Mods:
1) put on the 8" drop receiver (lowering the front of the trailer "sail" another 3"). It is now slightly tilted down forward on level ground -- not sure if that's better or worse for aerodynamics. Maybe I'll just need to buy a 6" drop.
2) filled the void between vehicle and trailer as much as practical. Drempt this up and just had to try it.
3) used the cap rear window as a deflector. Not sure how much this helps, but it sits down nicely against the tarp at speeds over 40 mph. Makes a slight deflector over the tubes and introduction of the trailer.
The problem with most fillers between the tow vehicle and the trailer is they don't accommodate turning. I loved the spandex idea used with the VW towing the trike trailer, but they also had an issue with turning and took it off when exiting the highway.
So, stacked 5 truck tire inner tubes on the tongue. They fit pretty close against the truck, but "move" when turning. I then wrapped it with a tarp and taped it to the trailer sides for better streamlining to the trailer. It looks totally red-neck.
Amazingly, the way I tied the inner tubes at the back keeps them in place beautifully. So well, in fact, it is hard to move them enough to access the hitch -- and impossible to use the tongue jack. Had to lift in on and off via strong back.
Anyway, I'm jazzed to try it. Any bets?