I find when I import poser content into Carrara with Transposer, the default setting is 1 poser unit to 20 Carrara units.  Based on that, when I import a Carrara OBJ into Poser, I scale the object (in poser) to 5%.  This seems to work for me.  Just make sure when you import into Poser, you uncheck the 'scale as percent of figure size' button.

Regards