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In my experience, dry sanding is quickest. There are several brands of sandpaper, not all of them last the same time.

And be sure to use 'dry' paper. Not 'wet / dry' I have done several...

For a blade like that, you can count on 6 - 10 hours of sanding before the pitting is gone.
I never leave pitting on a blade. Otherwise what's the point of sanding? :)