Is there a deadband you can mess with?
Maybe additional coad could be thrown together that would slowly center your view after a few moments of relatively little motion.
Would a button or a key that disables head tracking work? Your view is skewed, only way to center is if you contort into a funky position (i read this happened to you Pongo). Hit that key, center your head (and ingame view), release key, and trackIR now detects this as your recalibrated dead center view... ?