My own experience is with 3DS Max, but I guess it can be applied to any modelling package. Poser works on a really tiny scale, compared to most other apps. When working in Max, I usually load a M2 figure for reference (it's imported at about 1000x size if I remember correctly). When I export the modeled object, I reduce the size by 100x, then load it in Poser (do not use the 'percent of standard figure' option and the object will be loaded at its original scale) and rescale it to fit. I then export the result from Poser as an OBJ and , eventually after processing it with UVMapper, I import it back in Poser where it now has the proper size. There are a few export/import cycles, but this works nicely. So , to answer your main question, you should take care to get the proportions right but not necessarilly the scale, as that can be corrected later.