The filter already uses a Kalman filter for position (X, Y), size (W, H), and velocity (X, Y), which can be controlled using the Stability setting. Velocity is currently only used to smooth over intermediate frames where no new data is available, but in theory it's possible to use it to enhance prediction of future movement at the cost of accuracy, however that is not a feature that is planned.
Note that the offset is relative to the detected face area, as not all faces are the same, and it works well for the purpose that it has. I'm not exactly sure what you are trying to do with the offset, but it seems that what you are trying to do is outside of the planned possibilities. However you can do the change yourself by forking the repository on Github and changing the values on these two lines:
1,
2. Once you commit that to a branch on your fork, Github Actions (on your fork) should automatically start building binaries with your own changes which you can download and install - just note that I can't offer support for custom builds.
I'm aware of the glitch where it just decides that the bottom left 1x1 square is really really important. Haven't figured out the reason for it yet, but I'm trying my best to find it. By the way, please use the StreamFX menu which has a feature request link to request features. I can't keep track of features requested here, and all development happens on Github anyway - best keep things in the same place.
