If you had a monohull you would have trouble getting more than 4.3 knots in winds over 6 knots.
A mono would do better (proportionately) at the lower wind speeds mainly because of mast height. We (catamarans) got killed at a drifter finish with a bunch of monos for that reason once at the Gulfport to Biloxi. Actually was pretty amusing seing all the monos crammed up and cursing each other going dead down wind as we tacked back and forth (it was faster to tack , probably more to do with getting clean air).