i think perhaps you're misunderstanding what these different tools do.  Matmatic is a mathematical interface to the Poser material room.  it helps you to create relationships among nodes programmatically.  so if you wanted to create a perfect skin shader, Matmatic is the perfect tool .   VSS or the Versatile Shader System, is an interface for controlling materials.   so if you want to actually control how the skin shader is applied to the figure, you should use VSS.  Matmatic came before VSS, so it does have some material control, but much less advanced.  iirc, bagginsbill has said he is building Matmatic support into VSS. 

at least, i think that's correct.  i could be totally wrong.

perhaps i've misunderstood (completely possible), but i think you shouldn't be using the collections to manage materials any more.  i believe that bagginsbill's intention is you should use the VSS control prop to control them.