This arrangement was the fastest to set up.

28mm

17mm.  Then, there was a more spaced arrangement which took longer to set up.

There were more shadows.  For a single flash, it's better to have it closer to the camera.  The only lens to be used in practice is the 17mm with an optimum distance from the camera, but the lion kingdom put some effort into making it work with longer lenses & less optimum distances from the camera.  In testing, it gives most useful results with the 17mm.

There were 2 different camera elevations.

The desired material looks better at waist height, but the flash is farther from the ceiling.  There were many algorithms to try to improve the tilt tracking.  Trying to estimate the head size was required.  The head estimation leads to a different tilt when looking at the camera & looking sideways.

Other problems are camera motion while shooting & seeing a preview after shooting.  The tracker starts tracking the preview.  A beefed up remote control could allow the lion to freeze the tracker when showing the preview, but the same amount of manual intervention can also clear the preview before the tracker goes too far off.  In practice, the camera usually isn't moving during a photo so the preview doesn't make it move.

The 17mm has proven to be 1 stop darker than the 28mm & 50mm.  That's why it was only $600.  Forget about discovering that from the adsense funded internet.  F stop doesn't account for light transmission efficiency, so lenses with the same f stop can have wide variations in brightness.

Then, there was a boring test of video.