actually thats not going to work, Poser will invariably read the wrong runtime, you need to overwrite V4.1 with V4.2 in order for everything to work correctly, both Poser and studio have a really bad habit of reading the wrong Deltas file when loading morphs. (possibly completely disconnecting the second runtime from your poser library system when you use her, and do the opposite when you use V4.1, might work, but its not recommended). as far as the joints and stuff you mention in your first post there is absolutely no difference between the two. the joints are exactly the same.