Headtracking - realistic degrees setting?

[sniperton]

I use FreeTrack + a DIY 3 point IR LED clip + a cheap camera. Refreshment rate about 30 FPS, a bit slow, but still OK.
Anyway, 10-20 degrees of physical head movement seems to me too small to convert it smoothly and accurately to 180 degrees in-game movement. I rotate my head 30 or even more degrees to the left and to the right to have a +/-150 or so degrees in-game movement (which is realistic IMO). Important is that your sensitivity curve shouldn't be linear: it has to be less sensitive towards the center to suppress unwanted display frictions when aiming.