Skyn --you may have a better optical effect by adding a dark colour to the underside of the wing. You will get more contrast, plus there will be no competing "tone" effects (light tones on top & bottom). At a distance, colour resolution quickly fades, while tone contrasts remains readily visible. It is usefull to have the upper side light (easy to see the sunlight reflected off it in a turn) & dark on the bottom -- not light, so therefore, the bottom).