The screen size recommendations do not apply to head tracking as it is not dependent on where you are looking on your screen.
For eye tracking, we need to track where you are looking on your screen and therefore the maximum screen size supported is 27" for 16:9 and 30" for 21:9.
Windows interaction requires good accuracy which can only be guaranteed within the supported screen area.
For gaming, a larger screen can work pretty well even if it is not recommended because the software will automatically adjust to the maximum supported screen size area. So please keep in mind that the tracking area will be centered and we, therefore, cannot guarantee good accuracy performance outside of that area.
If you are using the features Free View or Extended View, the in-game camera will move according to where you are looking and it does not require such a high level of accuracy, so camera control features can perform quite well on larger screens too.
If you feel uncertain, contact our support for more information.