I too have had one of these bits languishing in the drawer for far too many years. Setting the height and fence is certainly a challenge and disuades very effectively.
Watching your video however, I had some inspiration to avoid the dreaded “imaginary” midpoint setting.
The peak of the groove must be a finite distance from its matching tongue in both height, and depth.
By all means calculate the midpoints location for the board thickness, but if we add 1/2 these values to the respective adjustments we should have a far more repeatable point to align the measurement device to….
Carbitool should even be able to supply accurate figures I’d suspect!
I just need to obtain an accurate height measuement device as you have used to verify.