While what you say is true .... in the old price list that , IIRC, you posted some time back, the Y/G was the most expensive of the Eschers. Bringing way more than the Dark Blue for example. Was the pecking order of Y/G, light green, blue/green, and dark blue based on rarity of the harvest or on efficacy of the hones generating higher demand ? Hard to say. Tony Miller used to sell current Thuringans as well as vintage, Eschers among them.

He told me, when I asked which were the 'best', that he couldn't say for sure, but that the rabbis who came to him for stones for their kosher butchers were only interested in Y/G. I asked Lynn and Tim Zowada which they preferred and both liked the blue/green best. IME the Y/G is my favorite and I believe Sham also like the Y/G the best. I must say that I have a couple of blue/greens that are absolutely great so it is hard to say. I've also had a dark blue, that I sold, that was really a great hone. Slower than the Y/G or the B/G but left a really fine and keen edge. So perhaps it is best to say that they are all good. YMMV.