After a c12k and a very slow (but satisfying) asagi, I'm a bit sensitive to the speed of any new stone. I'm looking at coticules. Certainly the cutting speed w/ slurry is much faster, but since I'm looking at it for a finisher only - mostly for heavy sheffields, I'm curious what is considered fast for a coti when using water only - no slurry. For example - how many strokes would a fast coti take to display unambiguously darken water w/ metal swarf? Or would that be a valid measure of speed? I understand that slurry makes them cut much faster, but how would you gage the speed of a coti on water only - as a finisher?

Many Thanks in Advance