I managed to figure them out after buying Anton's Spywear at DAZ (which are also really nice illustrations of the power of AltGeom dials). You are pretty much on the money. Body handle is actually a little bit of geometry (I suppose you could slip in a call to a poser primitive instead), treated like a regular body part with parent, weld, and so forth. The first one I got to work I did by including it into the heirchary when I made a character right in the window (Poser 4). What it can do is give you ability to apply rotations to a small zone (defined by spherical zones, of course) of an otherwise contiguous mesh. I have not yet learned if you could do translations in the same way you can with a magnet. It's just a thought, really. Most of a cape would be better with body parts and some key morphs. And for one of those long, trail-in-the-wind types, maybe a lot of body parts and some EasyPose dials....