I tried out the hip tracker cup meme. Got a sturdy espresso shot cup (those bathroom dixie cups are too flimsy), cut some holes in the side, threaded a belt through. I don't have a 1/4" screw and washer, so I just rubberbanded the puck on as a test. It stayed on well enough.

Even though the cup is only 6cm tall or so, tracking is quite a bit improved from having the puck right against your waist. No slight jittering or flying away. Having the sensors on the edges free from occlusion really helps it seems.

Downsides is that you now have this awkward cup sticking out of your waist. It's not too bad just lounging around, but if I was dancing I'd probably whack it at some point. Also at least with the flimsy belt and cup, the tracker (and your VRhip) jiggle around a lot. To make it more robust you'd have to get a larger belt or some sort of solid plate that goes against your body, like a big belt buckle.