You can (and should!) adjust the head tracking sensitivity once for every game on the head tracking page of the vorpX ingame menu to get perfect 1:1 tracking.
Completely disabling it doesn’t sound like a good idea to me, but if you want that for some reason, you can do it this way.
Just in case: if you didn’t do so already, please read the Essential Game Hints in the help. This and a few other very important things are explained there.