Ive had a few stones like that, I returned them as i was looking for a finisher. The nagura is harder than the base stone it seems. It may be a great pre finisher, but sometimes soft stones like that can release bevel killing particles. Cant say for sure though. You say the stone doesnt self slurry much? I use a blade on a clean stone then use a paper towel after to see how much slurry is released water only. I typically do on any new stone 100 half strokes to see how chippy it is or isnt. Look at the scratch pattern with the loupe water only, then with slurry only to see whats what. Anything too scratchy I have sent back though.