Sorry, I meant what tracking hardware are you using. In either case, you can apply an offset to the tracker link. Example:
Code:
#Add 6DOF tracker
tracker = viz.add('tracker.dls')
#Link tracker to main view
headLink = viz.link(tracker,viz.MainView)
#Apply offset to head to account for physical tracker offset
headLink.preTrans(0,-0.15,0.13)
Let me know if you have problems with this.