Well, if you guys are to do a speed trial type “open Footy” event I would think a “French Trench” style course (beam reach with a flying start on one designated tack) is the way to go. Wind over the side of the boat will reduce nose diving and broaching while providing the greatest potential speeds. Ditching the box for a simple overall hull length measurement of 12 inches would allow for beamy skimming dish type hull forms and/or out-rigged foils, or my favorite, a proa configuration with a telescoping offset arm (Aka) that holds the r/c gear and batteries with perhaps additional weights that could be added as the conditions warrant. I would also think that extending the course length to 75 feet or so would provide a better averaging of speed over distance.
My two bits.