Just another suggestion: Borrow the bump map layer, for the default skin and apply it globally across that model. I only ask, as I believe that it would save a ton of work by all of the skin contributors to replicate this work, and it should be the standard shape, unless the contributor feels they have one of equal quality. As it is, the converted skins have lost some of their 3 dimensional feel when lighting reflects over a seemingly smooth surface, unlike models with a proper bump map.