I've been creating morph targets but using a fish as the subject to be morphed - the principles should work the same though. I found that exporting with the preserve groups option checked and 'as morph target' is essential, otherwise you get a "jumping" effect as the unmorphed object tries to go to the xyz space of the morphed object when the morph is applied. I found it good to freeze the adjoining vertices if possible while creating the morph in any one group before sculpting that group to avoid seam problems. Sculpting the entire mesh all at once never seems to work for me; the groups all respond as individuals to my deformations and overlap each other - scaling in particular will cause this to happen. I also discovered that some morphs just don't work, no matter what you do. Details are crucial. If you must experiment, do it with only one thing changed at a time and keep everything else exactly the same. And oh, did I mention? Save, save, save - but in increments so you can always go back to the last thing that almost worked. Good Luck!