Over 50 years ago there weren't that many good synthetic hones available. For honing razors and scalpels and other presicion cutlery, people formed the edge on softer and quick Coticules, before going to a harder and finer Coticule for the final polish. They had found through decades of trial, which Coticule veins were best for carpenter use, which for razors, which for leather workers, etc.
That's basically what I read in a small booklet, written in French about 40 years ago, about the use of Coticules. I'm not sure how scientifically sound the grading of the Coticule veins was in the old days, and I'm even more puzzled about the relevance of it all, today.
I never found much variance in the polishing abilities of several Coticules, when used with water.
I think it's more important that you told Rob the purpose for your hone, than what label (Kosher, slelect or standard) it is carrying.

Bart.