and hey, I used to practise BaGua. mud-stepping, circle walking--never got to the end of learning the linear form, but really do (did) love it, spec. the circle walking. "weirdly beautiful", it's called. This description was what first inspired/attracted me. That, and my then-partner was doing it, along with some other martial arts. Circle-walking together was fun.
I'd love to take it up again. . . now that you bring it to mind. About the Chi machine; I've always imagined I'd find an "off-centre" oscillation really disturbing. I'm imagining you'd be able to tell if it was off. the speed you like sounds just right, to me. Gald it's doing you good. I'd like one--maybe one of these days. . .