what source of light do you use ?
if PS Move then I am really sure it should work very smoothly once you have exposure properly done.
For seated position it should work extremally well because you can put kinect close to you like 1.5 meter and have big ball easy captured.
If you still have problem we can have session together and I will see where problem is.
This is how I have it for colour tracking of hand (same is for head).
First of all, in Filter view (right bottom) you see clearly the ball. Then on left bottom in rectangle you see Tracked colour is also red that means it was properly identified and detected. It is already evening and I have only nomrmal light but you see that basically upper right window is black except of ball (this is not required though).
Then on bottom left you have some data. Tracker posision is 2d coordinate that should smoothly go with your ball as you move it smoothly.
Depth should also change smoothly if your moves are not violent. Of course they can be fast but I want solve head tracking problem first.
You can tell me if you can observe all I have mentioned here. Let me know. Alternatively we can set up a session on skype or discord.
Greg