I tested different wing angles today. I built adjustable braces and found a hill that is .9 miles long. My procedure was to put it in neutral at a mile marker at the top of the hill while traveling 55 mph, and then see how much speed I gained by the bottom. To make a long story short, at the low and high end of my adjustments I could reach 60.9 mph, but I found a sweet spot right around 10 degrees that would take me to 62.8 mph. I made about 20 runs in order to be sure my results were repeatable.
In my final run I removed the wing entirely and hit 65 mph.
Back to the drawing board.