Hi @efroe, thanks for your query.
Firstly, it is absolutely crucial that you calibrate the Eye Tracker properly. Not only with an attached screen as intended and designed but for each individual user also.
Changes in eye structure from person to person although subtle, lead to significant changes in the eye tracking algorithm so certainly there is not (or will be) a ‘generic’ profile you can use.
In terms of working without a screen, the Tobii Tech Range of Eye Trackers (4C, Eyex, etc) are designed to work on a screen setup *only* so any change to this setup will inevitably lead to problems of accuracy. It is possible to remove the screen after calibration and replace it with a similarly angled and sized alternative stimulus (say, a book), but again this is not a procedure we can support. For these kind of eye tracking studies, you would need a Tobii Pro range of tracker that does indeed allow for such a custom solution.
Once you have run calibration properly according to the specifications I have outlined, please let us know should your issues persist.