i would agree that even the soft Ark seems to be a little on the fine side for real grinding.
To me even a 1000 water stone is a bit slow for "real grinding."
With oil stones a crystolon stone is about the fastest cutting in my collection. For a deep knick or other work to remove a lot of metal, diamond stones or sandpaper may be a better options.
For me the water stones below 1000 wear too quickly to be of much use.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)