I am not an expert at all! BUT
My 3 finishers are a coticule (that is very very slow), 12k ss, and a thuringian. By hht they are all pretty close, unless I do a 0.5 micron diamond strop after the 12k ss, which gets scary sharp. I have tried the coti and the thuri either after an 8k ss or after the 8k ss + 12k ss. Not sure there is any improvement to do the 12k prior to the natural stones. probably a waste of time i.e. redundant. All of that said my most comfortable shaves are probably from coticule edges. I need more shaves to say that its true all of the time, of course. Now I want a japanese stone to try etc.