Michi
I dislike attempts to rewrite history
I have the Cerax 3000. (Not sure whether that's exactly the same as the Ouka.) It works fine for touching up for me, and as a finisher for most of my knives.I think @Michi liked it very much for the latter, maybe he can chime in for you.
I rarely bother going above 3000 any longer, except for my yanagiba. I find that a 3000 edge is plenty sharp enough for cooking, and it retains some bite so it doesn't slip on tomatoes.