This thread got started because I admitted to Larry that I put the flaps on the wrong wing panels of my symmetrical-panel Oriental Plus. I had mislaid the plans and figured the narrower flap should go on the outer panel, due to slightly greater speed and need to avoid rolling on flap deflection. David looked at it at one of our trim sessions at Davis and said, "That doesn't look right." I contacted the designer, Dee Rice, who confirmed that, yep, narrower flap on inner panel. Flaps are equal length but one is narrower chordwise. Now I have a tab on the (wrongly) narrow outer flap and cut 1.5" off tip end of inner panel flap. Live and learn. It is somewhat comforting to learn there is no real way to figure it out in advance as a matter of design. Flaps were glued to hinges so no easy way to swap panels.