Primary Specular Map - This map basically controls the specular highlight that has a more diffusive falloff. I definately give credit to "d'artiste Character Modeling" book and Francisco A. Cortina for these next couple of maps.
Secondary Specular and Reflection Edge Weight - This is just the Primary Specular map with noise added to it. It'll give a nice broken specular and rim reflection.
Reflection Weight - This is a very crucial map. It can really enhance the reality and believability of the skin. At the parts of the skin that look wet like the lips and the tear duct your probably gonna want some reflectivity. You can also get a glitter effect by adding high frequency noise where the makeup is in the reflectivity map. Create an HDR sphere and you can definitely notice the results of the reflectivity.
Again, I am by no means an expert at texturing with the misss_fast_skin, but hopefully this can get you on the right track and serve as a starting point. I would also like to give thanks to the "d'artiste Character Modeling Book." It has some great stuff in there on texturing, shading, and even hair!