You will definitely need that 3 degrees of washout to compensate for those terrible reynolds numbers you will be operating in. Remember that cruise speed is typically double that of the stall speed and is about as slow as you want to go in normal manuvers. Even at 16 oz wing loading which is extremely low for what your doing, that would put you at a 40 mph cruise speed. It is more likely you would be in the 32 oz wing loading so something more 50-60 mph range would be more likely.