I'm sure you've answered this question already, but what website do you use to check what sets are most common on pokemon? Also, would you be able to make crawdaunt workable at all in an OU breaking core? I've been able to get it on the field safely by swapping out the Hoopa-U on your OU Hoopa-U team, but was dismayed to see that meowscarada just did the job better most of the time.
I don't think Crawdaunt is OU viable, stall teams can actually wall it pretty well these days, and other archetypes kill it pretty easily. Stuff like Raging Bolt and Wellspring also make running Crawdaunt pretty rough. I don't see it working, but I could be wrong!