Well, for morphs I always use the software in which I modeled my cloth. (in my case, Cinema4D) Simply because a 3D modeling program has more tools to make every morph look realistic. If you're not using another 3D tool, I think it's difficult to get the morphs right within Poser. So basically, I would advise you to model the morphs in a modeling program, then export as obj. and import the morph in Poser. Please be aware that I'm no expert on this area, I'm just letting you know what I think was the easiest way for me! :) Take care, Sabra