Is there any chance you could give a bit more of an explanation on what you mean by success? I would be quite happy to write up an answer for you, but if I could have a better idea of what exactly you'd like to know that will help.

I'll follow up with more later but while the system was actual quite effective the issue with it, like with many systems, was succession. While a central part of the original design was to avoid hereditary succession this did not last.