Update / long-term report:
I will never use a lesser windscreen than this if I can at all help it. A 400-mile day ride with the Super Charger was very manageable with this and the Corbin seat. The Corbin seat helped me see over the top very easily where my ability to see over with the OEM seat was marginal (unless I removed the spoiler).
I consistently get better mileage than my ride partners at all speeds below 75mph, although trying to get a consistent measurement in consecutive runs by comparison is fraught with statistical noise where I live. I've had 100 mile rides at 60-65 mph, and if the air is clean, a 55mph ride could last 115 miles on my 16 DSR with 13kWh.
The benefit is lost in a heavy headwind, however. I faced heavy 30mph gusts going north on US 101 towards Salinas in the afternoon, and achieved a projected range of 75 miles going at 45mph. It is hard to say whether I would have faired better without the windscreen, but it shows that Terry's Vetter fairing is clearly superior in headwinds.