Throwing away the roughness map when using a node, like the PhysicalSurface node, that is made for a metal-roughness workflow… and using a specular map instead even though the metal-roughness workflow does not even has a definition for it… good luck.

For a complex skin shader IMHO you better go with a custom shader. And even than its still not easy to come up with something you have in mind. Thats mostly due to the limitations of the Cycles SSS node. Personally i gave up on creating an advanced skin shader. i came to the conclusion that i would have to write a custom shader node for it which is not possible in Poser. Please proof me wrong on this :-)