First, about the eye offset: I have delved into this a bit more, and verified there is a problem with the eye positions with my Acer MR headset. Here are the eye offsets for a Vive; the top numbers are the individual eye offsets from the head center, and the bottom numbers the difference between the eye Views:
Note the symmetric X translations, and no rotations. The differential does not change with headset orientation changes.
Here is the Acer:
Note the left eye is at the center of the head, and the right eye is shifted the entire inter-ocular distance, plus has an X rotation. Way bogus. I suspect that since they are not symmetrical, that explains why I see the eye View differentials change with head orientation - does that make sense?
I looked in the VVVV.plugin code, and do not think the fault lies there, rather that OpenVR is reporting bad data for the Acer MR headset. I'll report this as a bug at OpenVR/Steam.
Concerning the time glitches on movement, turns out that happens when the scene is too complex and the FPS drops below about 40-50, getting quite severe if it gets down to 30fps. It does not happen at all if the FPS is above 50; this is on a notebook with an i7-7700HQ and GTX1060. For some reason the MR compositor degrades much less gracefully than the Vive at lower framerates. I'll poke around more on it.