The most significant thing I noticed from building and flying home built full scales is from the time of completion and first flight of the aircraft with cloth covered wings and ailerons I could see just how much the wings and ailerons would puff up in flight, and what my best level cruise speed was. Now after the airplane spent 8 to 10 months the hanger in the heat of the Mojave Desert the covering would draw tighter and I could easily see the effects during flight, not to mention the aircraft cruise speed when up. So solid covered wings and control surfaces are much better for obtaining higher top speeds due to the lower drag coefficient of a thinner/stable airfoil during flight.

Bob