Hello,
I was also looking for a customized calibration (own design and wording), found some post about Gaze SDK, was confused by the presence of this site: http://developer.tobii.com/tobii-gaze-sdk-4-0-2/ and hoped for the Gaze SDK to be still active.
I guess there is nothing I can do but keep checking?
Would it be possible for you to post here, then I get an e-mail 🙂