FH, it was shown in some very early windtunnel work on duration indoor models that the typical sticks at that speed did little to upset the laminar flow. The turbulence from the exposed leading and trailing edge "spars", if you can call anything that small spars , was so little and damped out so quickly at the speeds in question that covering the bottom was a waste of time. Just as you found out using the empiracal method.

Still, it's nice to know that you and Frank Zaic (IIRC) learned the same things...

I got this from a very old magazine article on indoor aerodynamics. It came out sometime back in the late 50's or 60's I think. Too many years ago to remember.