you can add more contrast and better define the form by painting in a light source. universal approach for this is to define the light as if above the character.
they will be different because they got different materials, the UVs just define where on a texture to get the information from, the materials define what the information is.
jocose: That's not exactly right. :\ That is a 2d art tutorial. In 3d: Specular maps define the brightness/color of a highlight. Gloss maps define the size of a highlight.
what kind of savage does that? ;) Cluster is just innaccurate - it doesn't imply connectivity which is a defining characteristic of a component/island/shell/hull/element