Quote - personally, i don't see anything but disadvantages for a separate lip UV.  sure you could scale the lip map up for detail, but the idea of having different levels of detail for the lips and the rest of the face seems artistically bizarre.  i literally can't imagine the scenario.

Would it be possible to change lip mats from one character (texture set) to another easier if the lips are uv-ed separately ? If so that would be a huge advantage in my mind. But I don't know much about this stuff.

As side note I think I have learned so much from this thread, about how poser works, character creation, there firefly fans hiding everywhere, etc.