I use kinnect v2 for seated tracking with PIMAX 4K. I use the kinnect just for positional tracking. Although it doesnt work perfect, is perfectly playable and i actually play all of my simulation games with it.
You have to position the kinect at 45º from you and configure the settings.
Greg, i continue thinking that if you add a raw data filter to the kinect positional tracking it would work really well. For me, just do weird movements when facing the HMD to the kinect, because the kinect take the position of the HMD as if it was my shoulders and vice-versa, so it jitters in the Y axis.