Yes that Gamma value is correct. 
Ok here are the PM nodes.  Now I'm no expert on these but I'll explain the ones I use the most.

PM: Color Tint
Pretty self explanatory.  You can use to give the your skin a tint of color (duh:)  Just be aware that this will darken the skin.  You can use PM:boost to counteract that.

PM:Bump
Adjusts bump strength.  This will vary greatly depending on the bump maps you have on your figure.  Sometimes the bump on the lips is way too strong while the rest of materials are ok.  I usually correct by going into the lip material on the figure or create Template Lips material on the VSS prop.

PM:Shine, PM: Shine Spread and PM: Shine Level.
Ahh these are my favorite and I know bagginsbill is pretty proud of this little invention.  This controls specularity in a masterful way.  When you adjust PM:shine you affect both the spread and value of specularity.  For example, if you increase the Shine value to 1 you'll get a stronger and narrower specularity.   So if you want to adjust specularity, first adjust PM:Shine.   If you then want adjust the level or spread separately you use PM:Shine Spread and PM:Shine Level.

PM: Diffuse Reflectivity
Controls the Diffuse value.  I lower this when rendering with IDL but you probably don't need to worry about it.  Feel free to experiment with it though.

PM:SSS, SSS Color and SSS Falloff
Subsurface Scattering. Actually this is fake SSS.  I sometimes change this to a blue color to make the skin colder.  To be honest I don't use this much and I usually keep this low since I always use IDL now.  Experiment ;)

PM:Boost
This boosts the effect of VSS.  This can be good when you add a color tint to your skin as it lightens it.  This will also affect specularity so might need adjust the Shine value when you change this.

To get a sweaty/wet skin try a PM:Shine value of 1 and a PM:Bump value of maybe 0.05 - 0.08.  Make sure your using Inches.

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