Thanks for this update.

I have to be honest to tell you that I didn't read all.
The rules in Europe regarding, for example, woodworking machines and tools are different for professional and DIY users. A dado as known in the USA may be used by DIY ers in Europe, but for professionals it is forbidden. But to be clear, a dado for professional use in Europe is and always was allowed provided it complies with EN 847-1 rules. One of the requirements is that the saw blades must have a mutual rotation lock (The CMT ones have a recess in their blade).  But usually this are two pins, which also ensure that no forces can be exerted on the nut with the mandatory braked engines. These pins are normally in many cases located in the flanges. Then there are two holes in the saw blade. 

The dado shown above does not have these locking holes and, despite the rotation lock between the blades, does not meet European EN 847-1 standards, for use on machines with a stop brake. It should be noted that in many cases a braked engine is mandatory.  In addition to two holes in a saw blade, a wedge lock is of course also permitted.

After I had written down everything above, I also looked at a CMT dealer website, and it clearly states that it can only be used with mechanical supply.
CMT product description: The CMT groove saw set complies with the European safety standard for mechanical feedthrough (EN847): CMT recommends not using this set for manual feedthrough.

So for professionals, this dado is in europe not allowed on circular saw machines.

https://dutchypatterns.com/