I'm making some progress in this area by getting rid of the Poser head (it always looks Posery) and replacing it with a head-like prop created in a modelling program using a photo as a template. I then use the SAME PHOTO as a texture for the head in Poser (you need UVmapper to add a UV map to your prop). It seems to work best if the head prop lacks detail which might clash with the photo. Let the photo texture do the work. This method means you lose the normal Poser face posing capability but you can still change the expression using morph targets for the head prop - the texture moves with it.