Well, since many of the hones you listed are natural stones, there's also the issue of variability. My CH12k is as fine as some of my Thuringians. I have a Coticule that is the hardest hone I've ever used and is as coarse as most Belgian Blues, but then another one is almost too soft and polishes better than the CH12k. One of my "regular" thuringians is finer than one of my Eschers, but not the others. And then there's the Japanese hones that run the full range of characteristics depending on what your looking for.
Confused?
There are many routes that lead to "the best edge", but your current setup is good enough that you may want to consider any further acquisitions to be for the sake of experimentation rather than purely for improvement.