From what I know, you can only "conform" a figure (character) and not a prop (which does not have body part names, joints, bones, etc to act as the "guide" for conforming. when you have all this common detail, you can "conform" with greater precision. Parenting, on the other hand just locks two parts together with a set of fixed relative offset coordinates that may or may not need to be changed when a figure is posed and re-posed. I have found that parenting is most stable when it is originally done with the Poser figure in the default (arms-out) position AND IK turned OFF AND "zero figure" button pressed in the joint editor when the "Hip" is selected. Do all of this BEFORE parenting, and your object will track the body movements MUCH better than any other method, but still may need tweaking.