I've fumbled around with all the import/export options, and I've stumbled once or twice on the right options to keep the morph in scale -- But I find it much easier to work in a size more suited to Carrara's workspace. Thus I go ahead and import "normally" and do what I need to do, then I export the new morph to Poser and carefully line it up by hand with the original. I admit, this would lead to vertice-shiver, esp if I tried to do this with phoneme morphs or other subtle facial morphs. But it works very well for the kind of body shaping stuff I've been working on.