On "Mmmmm" we don't have a masthead wind indicator to record windspeed and/or direction. Nevertheless, we've had the old J30 Polar chart on the boat since we bought it years ago and use it as a guide. We do try to sail to targeted speeds. After sailing for a while, you get pretty good at guessing the actual windspeeds and using that, along with our speedo, we shoot for targeted speeds. On beats, we know what that number should be on our speedo. On reaches, we simply use our Windex indicator which have the jibing angles set. Granted, it's not "data driven," but it keeps us in the ballgame.