I think this should help out http://www.marmoset.co/toolbag/learn/pbr-practice In this case... diffuse = albedo roughness = microsurface specular = reflectivity
Thanks for merging my post here. Here's a great character lighting guide by Marmoset by the way : http://www.marmoset.co/toolbag/learn/character-lighting
Sorry ´bout the small pick. here a a new without specular. this got 1024 maps. As the other pics, this is rendered in toolbag using the marmorset engine.