I usually think of posture as being from the hips through the head, and my legs go where they need to so I don't fall over 8) I've done the jump-and-land exercise a bunch. It works pretty well. The only problem is that sometimes it creates a static or locked body position because people think they need to stay right where they end up. The body needs to be free to move energetically and in balance, in various directions, and with good contra-body movement. Oh, and when in closed position with some stretch/counterbalance (e.g. middle of a swingout) followers are almost always more vertical to support the connection, because if they lean forward the lead's hand slips up oddly and the hold isn't good.