Had to take a side-road down Matmatic lane. Finally got it running in re-installed Poser 6. I carefully did the exercises on the Node Cult site on the simpleShader.
Now, I realize everyone has moved way ahead here - VSS is light-years from this - but I had, I just had to. I have to understand what goes into a shader script, and doing this exercise opened up that concept. So, this way, I can now look at what's included with VSS... one significant difference being what matmatic used was an mm1.txt file, and VSS seemed to include this vssGenericFigureShaderRules.py file. Am I barking up the right tree?

Of course, there are hugely significant differences, as in a completely re-thought shader tree. But, if I wanted to do a shader, I had to study all this. If that lightning-bolt of genius finally knocked me off my perch,  could basically use the same code in a mm1.txt file for matmatic to generate a material file, or copy it to a .py in IDLE, making sure I have the right headers, right?

Boy, am I tiptoeing into some wild terrain, here.

Having fun with the results, tho...

This is with the lights as defined in the tutorial, V3 with her V3(Body/Head/etc)Hi.jpg texturemaps, having applied the simpleShader1-8 of the new, improved group.
Okay, back to your latest group of suggestions... just finishing the lips mask.

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks