I forgot to add a relevant note to explain the drag reduction:
There is a three-inch gap between the lower edge of the windscreen and the headlamp, so there's just the right amount of air flowing up from under the screen to minimize the pressure difference at the trailing edge, which keeps down the vortices. I definitely experienced strong vortices in initial testing with a naive lower mount!
My forum thread with the process I went through to make it work satisfactorily (link originally obfuscated because I hadn't made enough posts here yet):
Larger Windscreen:
http://www.electricmotorcycleforum.c...php?topic=5525