In Daz I can use multiple texture sets from different UV's all at once.. EG M4 UV for the body, My mouth as a V5 UV and my Eyes as a M5 UV? Can you do this in Poser as well?
Yes, but you need a .duf materials preset to switch the UV set - you can't do it through the interface.
I don't use Poser, but I actually heard before that it is very much doable. It's as Richard says, it involves a preset process.