Hi.
I wont be able to share the full model, but can the file for the shader set up. Even better, I can do a video for you on what iv learnt so far with Skin shading within Vray. Your right, there is so little out there, I had searched and found nothing, so I had to learn the hard way "Trial and error", thankfully, my past experience with Modo has helped me out here, but certainly not perfected it as id like just yet.
For skin I do not use the Advanced material, I use the Fast SSS2, or Skin material, and now even better the Alsurface which is so simple to set up. The SSS2 is best used with the Blend Material with separate Spec, Reflection.
I just got my motherboard back today, much sooner than I had expected, so Il try to get the file to you later on as its on the HD that the new Motherboard attaches to. In the mean time on my Temp PC il do you a video which should help clear some bits up.
Dan.