So these are just some quick results, long term tests and retention and the feeling on products during service would take quite some time.
The rika was the base stone. I would start both knives at this one and go on to the next stop. I did quite a few back and fourths and up and downs.
The rika many people here have used. It has become more of my base stone that I bring knives up to a small burr on. Some knives I go lower and when I need to do heavier work then I obviously go much lower. Rika has been one of my favorite stones, it cuts fast, builds a nice slurry, barely loads up, and is a pleasure to use. I recently used the geshin 4k and that stone is faster and works in a similar manner (a.k.a when rika dies I might have to get me a geshin 4k)
Next I went to the geshin 8k. This stones basically works the same as a rika 5k or geshin 4k but at a higher grit. And like those stones this one is a pleasure to use. Builds a slurry fast, cuts very fast, and has no loading at all.
The imanishi and jks 10k are very similar. I had to go back and forth multiple times to really get a feel for the final edge. As far as the feel of the stones goes they both load up and build little to no slurry. The imanishi loads up very fast, the jks builds at a slower rate. The both cut and work much slower then the 8k geshin but get the job done. I felt there was also better tactile feedback from the jks, but it is not a huge difference. Similarly with the final edge I liked the performance of of the jks slightly better. Both are well polished edges but I felt the jks cut crisper and would also bite into products slightly better.
I then went on a progression of 8k to 15k geshin. This was the technical sharpest of the bunch, had good but and would glide through products better then any of the other stones. The stone works slightly faster then the 10k stones, it does not build much of a slurry but slightly more than the 10k, it also barely loads. It does load a bit but not a ton. It has a similar smooth feel to the 10k but a much better tactical feel.
But my preferred edge was the 8k. Not the technical sharpest but i enjoyed the way it felt as it cut the best. It is a bit toothier. I have also stropped after all the stones to feel how those results vary but need to do more testing with that. I used the finished 8k edge at work for a bit now I am taking the 15k on the same knife to work to see how I like that. After I will repeat with the same sequence but finishing on a strop.