How did you have your Devour drilled? I drilled my strong (never paid attention to the numbers) But had my Rumble drilled with a standard pin up drilling, and used it on old wood lanes and older synthetics, (also kept it at 2000 grit speed 13.5 revs 375/400) and it was money for me.
If I'm not mistaken, your also Rev dominant, with slower speed.