ummmm.... Ive never morphed a group before, I usually do a single body part at a time.... but I can tell you that I usually parent the part to the magnet after setting the positions etc.... I find this helps quite a bit. Otherwise Id suggest trying to find a reference in Travellers tutorials on RDNA, if I remember correctly I think there may have been something of the sort in one of them....

Hope this helps

"If toast
always lands butter-side down, and cats always land on their feet, what
happens if you strap toast on the back of a cat and drop it?"

Steven Wright