Every ignition module has some internal delay from the time hole sensor provides the triggering pulse to the time when high voltage reach the point which create spark.
ignition module is analog device especially that part (transformer), which create very high voltage on the output.
depend on construction and core material that transformer will create high voltage on the output with some different delay depend on particular design and material used for transformer core.
the spark plug gap size is also contribute to some delay.
The larger gap the more delay is.
where I am leading?
it is not essential to do so precise 28 degree setup as shown on the video!
your particular ignition module, spark plug gap and hole sensor gap all going to contribute to your engine timing.
even fuel octane number will contribute for some differences.

on well running engine with 28 degree hole sensor setup any movement of hole sensor 3 degree in one direction or other is not making any noticeable difference.
i did it several times on different OS engines and found that moving hole sensor one way or another by ~3 degree doesn't make noticeable difference in starting engine and at full RPM.

AK