You can also delete un-needed morphs from figures. It is tedious, but it does reduce the size of the PZ3 files. Caustion, It cannot be undone so save frequently. Sometimes, I even unhide unused morphs so that I can delete them.

Many people fully texture, and morph characters and then cover them up with cloths that also have textures and morphs. If the figure has textured areas that will be completely covered with cloths, delete all the unseen nodes. If you are using a large scene. There may be parts that will be outside the render that can be deleted, or at least de-textured.

There used to be a python for exporting figures, with all the cloths and props, and re-importing them as props. They retained their morphs and textures but could only be moved after that. However, as a final step before rendering, this can save memory. I just can't find that python, but some one may remember it, or be willing to write one that works in Poser 7 and Poser Pro.

Probably edited for spelling, grammer, punctuation, or typos.