I do clothing JCM to run from the joints of the same figure, it seemed the logical way to do it. When you conform the item and move the parent figure the morphs work, even though the dials indicate the clothing's rotations aren't moving, of course. As to skirts, sometimes I do hip/buttock, sometimes (mostly) hip/thigh, sometimes you can get away with just hip mesh and the rest as phantom parts, depends what moves me that day! Poser will not do-inbetweens more than one part away, (that is, the joint parameters fall off zones and stuff only effect the next part back), so that comes into the calculations.