I tryed some standard and selected stones and from this experience I would not buy a standard Coticule for razors again but for knifes. I had a 200x60 standard that was pretty hard, extremely fast and fine for all kind of knifes. That stone surpassed all my other razor Cotis, two strokes and the water was black and the knife super sharp. But with razors this stone was not only slow, it was like honing on glass, even with slurry. The feeling was very strange with razors, zero abrassive, the edge got not sharper, useless for razors. That was very impressive to me, superfast with knifes, dead slow with razors.
My La Petas is optically pretty similar, blue spots, extremely hard and slow. But this stone polishes the razor relatively quick to an Arkansas like sharpness after an 8k and still gives a very smooth shave. I get not even a light grey slurry with it, I could never set a bevel on this stone, but it is definitely a gem. This stone is also very slow with knifes.
I had also a medium soft stone that I believe to be a Les Petas that was very fast with razors. Dark slurry after some circles. But this stone was not as fine as my superhard Les Petas, but still got a good shaving edge. It was bought from a dealer from Austria and was marked Extra-Extra, they do not use the term selected. It was a newly bonded stone, the glue was white. Like Ardennes Coticule they recommend extra-extra (selected) for razors and standard for knifes and tools.
I had one standard bout that was moderate on slurry but extremely slow on water. It was almost the same feeling like the standard rectangle but with a minimum of life in it. It took half an hour to polish a razor to shaveready, not very easy to use with razors, but an outstanding stone for knifes and tools.