fxt913, I had no idea that the coticule was a oil stone first and then a waterstone. a lot of what i read before buying said to only use water and didn't say anything about keeping a stone without using slurry for a "finisher" i suppose since i have two stones now (ugh) i can try this method.
----I lived in Belgium for a while....in mid-nineties..... and that is where I bought my first coticule. I was not happy with it, but was doing fine with my small (5x1) thuringian after as a finisher! The barbers I went to all were using coticules (but not openly offering straight razor shaves, only shavete, so you had to ask and beg...), and told me that "green" german waterhones are nowhere near as good as oilhones.....like coticules (used as oilstones for centuries), french, greek, turkish etc... They were using other oil hones to finish as well.....some weird, small black (now I think were likely Pierre de la Lune...), or black with white patches ones... and even told me coticules used to be sold with two three oil bottles (thin-thicker..). I was able to get very decent edges with oil or lather from coticules on several old Solingen carbon blades back then, and later on (from 2006 onward) superb edges after eventually following on Surgical black arkansas......but the "newer" ice hardened and/or sweedish steel blades did not do as well. Otherwise, my small thuri fixed everything for me all the time!
I must say we are getting spoiled these days with jnats, where we are experiencing higher levels of sharpness, and smoothness, and what used to be excellent edges in the past are "only" mediocre now. It puzzles me though that oilstones in general seem out of fashion for razors (some say they are messy....to me they are less messy, as they need two drops only), and even vendors dedicated to selling coticules (not just synthetics) seem to avoid the subject. We are lucky to have the many choices available now, so have a great time trying them all yourself, and stick to what you like!