Success!
Enable Developer Mode.
Click Debug → Device Datas
Select the Tobii tab and check the box next to Display TGI Settings (green circle)
A new window will pop up, expand the HeadTracking section (yellow circle)
There’s a setting called settings.HeadTrackingRotationResponsiveness (white circle)
By default it’s at 0.500. By playing with this slider I can adjust the amount of “laziness” at will. 1.000 eliminated it. At 100% it’s a bit too robotic for my liking, something around 0.800 or 0.850 felt much more natural but this will be a personal thing.
Much more testing needs to be done but this is the biggest positive change I’ve seen so far.
As an aside, there’s lots of neat options in the Device Datas and TGI Settings windows, such as the gaze preview (the red circle on the prop blade). It also makes tuning your settings much easier because you can do it all in real time and in-sim. Unfortunately none of those changes will get saved between sessions.
So today I learned that there’s much more settings under the hood than is exposed to the user via the regular Tobii controls settings. Hopefully the developers can open this up a bit more and we can have all the fine adjustments we’re looking for.