Hey, that's really great ... looks absolutely natural ...

Is it done in Poser's shader system or in a "full-grown" app like 3DSMax or C4D or only renderer specific ?

If Poser how will this influence rendertime? Do you have a mt5 so I could test a bit ?

I think the UV map is not bad only that the coordinates from back and front seem's not match exactly. But the polygons are running straight along the used seam. Only problem that the map is very tiny to be used for texturing.

But with such a procedural shader this should not be a problem as I understand.
Otherwise rendertime will also be no problem if using two different material collections. One with less/no detail for normal scenery images and a second one if making a closeup and also only if legs are in view.

Think we should give that a try ... means I will need a small example to figure out how to do so.

B.t.w. I just had a look to a other thread regarding "making surfaces glow". By using spot or point lights I have found that these don't respect physical limits. They illuminate things through non transparent objects like wall's or such. Mean's a person behind the wall will get light and throw shadows  as if directly in the spot/point light.
That seem's to be a poser and/or render engine bug. Did you have also such experience and might be you found a workaround ?