I read the topic.
Over the years, 1 GT had to be replaced. But interestingly, this unit works well for Thomas. I had a TB70. (I sold it). The problem was very similar anyway. First of all, don't forget that... If you use the setup wizard, the Gyro gain is 1.2X (I think there is 700X in the wizard). This can cause the tail to oscillate. After all, if 40% is set in the remote control, it is actually 48%.
Furthermore, I went through every part exchange. Bearings. Main shaft. Main gear. Tail bearings. Tail shaft. Etc, etc.
It vibrated. Both in diagramm and physically, based on the values seen. The diagram was useless in this situation. Everything was new. I replaced everything. The motor also. Actually, I could have bought another machine.
But it was a mission!
The dampener in the tail was bad. I only saw under a magnifying glass that it was oval and irregular. I replaced it and everything was fine. Then I sold it because I hated it. Of course it's a good machine. And my friends also have such a machine.
The Spektrum is not nearly as fine to tune as the Spirit. For years I just used the values given by the setup wizard in the spirit settings. (not agility) I don't think that the tail pirouette consistency value should be changed. Because if it needs to be changed, you don't even need Geolink for your knowledge.
Sorry, this is just my opinion.
In the moment I have 4 GTR w/o any problem.