Wow, thank you, BB! That was very validating. About that Rule Template Face - I wasn't sure how to proceed with that. I was kinda thinking class and sub-class (or perhaps super-class, where only those nodes that would apply to nostrils, face and lips (and potentially forearms and hands, since one does see them often in close-up portrait renders) but I think I would have to have a look at the actual script to see how the whole thing is built. So, I'll just leave it off, then.

Found a much-simplified tutorial by Sixus1 (Les Garner) which has helped support your discussion pdf (the one that came with VSS). Speaking of which, you'd intimated that you were going to sell the VSSPro program for little enough so that people would be enticed to buy any new shaders you might come up with subsequently. I know, you didn't exactly say that, but that was my interpretation.
I think that's an excellent strategy, BB. I for one see now (given the complexity of developing a shader) that putting one of these together - at least, one with this degree of sophistication - would be far beyond the scope of all but the most intrepid Material-Room die-hards. And, fair-enough, so it should be. This is your craft, your speciality (one of them, afaik... you would most certainly have others: you've built a consulting business around them) so it just makes sense that aspects of these shaders are going to remain enigmatic.

I've had to follow on fixing other people's code. In VBA. I know, nothing real exciting, but the code was complex enough that it took me a bit trying to sort out what the different function calls and procedures were doing. The so-called documentation... wasn't.
I find myself in the same frame of mind looking at a series of math-nodes connected to the alt_diffuse channel, then splintering off to affect everything else. It's all good, BB - don't worry about it - I'm going to leave this with you for now and just use your shaders, not try to figure them out. I'm currently setting up a website (store) for the PoserForDummies MSN forum members, so I've kinda got my hands full with tweaking php and css... you know how real life kinda gets in your way? lol I'd rather be spending my time truly understanding exactly what each node in your shader really does, how they all tie together, but duty calls. In the meantime, the more I contemplate them, the more impressed I am with how beautifully they are put together.

And the results speak for themselves.

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