Hi Julio,
As Jenny said, if the Windows tablet is running Win8 or 8.1 Pro there shouldn’t be any problems porting your game to the tablet.
Regarding mounting of the Tobii REX: The EyeMobile bracket or a similar solution works fine. Note though that when using the EyeX Engine to do the Display Configuration, the engine assumes that the eye tracker is mounted right below the screen with the provided magnetic brackets. If you use a non-standard mounting, it is recommended to run a custom setup, with the Active Display Area Calculator provided with the Tobii Gaze SDK.