You want to look at swell rather then wave. Swell is larger ocean effect. Waves are the more acute wind influenced effect. Waves are more wind based and aren’t really bothersome at most anchorages. Swell can be very bothersome when is rocking your boat all around.

In a big north swell avoid Honeymoon, Caneel, etc on St John. Maho and Francis are good. In south swell avoid most southern anchorages. Everything feels worse on a mono vs cat.

Instead of windguru, check windy.com

(Just my opinions and observations)