Augmented Reality: virtual world not overlapping real world correctly

[Vaquero]

Thanks for pointing out the double swap, Jeff! I overlooked that. Positional and querternion swaps are all set to work correctly.

It turns out that most of the issues I see are related to the FOV. Culprit are these lines:

import nvis 
nvis.nvisorST()

We do use the NVisor ST50, but Vizard's nvisorST() initializes settings for the nvisor ST60, which has a vertical FOV of 40°, whereas the ST50 has a vertical FOV of 32°. The resolution seems the same at 1280x1024 for each display. This is a ratio of 1.25.
So setting the FOV to these settings makes things much better, but not perfect. There's still quite a lot of rotation around the Y-axis when turning the head, but much less up and down movement. It fixes the scale of the perceived world, so the scale doesn't seem to be an issue anymore.

The ST50 has a vertical FOV of 32° as I mentioned, but a horizontal FOV of 40°, the diagonal (binocular) FOV is 50°. So I changed some lines to this:

viz.fov(32, 1.25)
viz.window.setFullscreenMonitor([4,3])
viz.go(viz.FULLSCREEN | viz.STEREO_HORZ | viz.HMD)

But as I mentioned, still not good enough, because the world ist still rotating with the view to some dregree and the FOV is close, but still seems a bit off.
I also turned up the sensitivity of the InertaCube4 in hopes to reduce latency. Are there recommended settings for use in VR with Vizard?

The LED that's tracking the HMD is 5cm in front of the eyes and 8cm up (on the top of the HMD). Would it be better to put it somewhere else? Or should I put 2 LEDs on each side of the interia cube and see if I can create this optical heading I read about in vizconnect?

[Vaquero]

The actual setting that reduced some of the movement of the world is this:

isense = viz.add('intersense.dle')
headOriTracker = isense.addTracker()
headOriTracker.setPrediction(50)

What's recommended for the other tracker settings like AccelSensitivity and Sensitivity, Compass, CompassCompensation etc.?