Bigger moguls are definitely a big challenge for any skier, what you will need to do when you get in them is to be patient, use as much range as possible, be forward and take a direct line. Also, backside pressure is important. You can get away with not doing it on smaller moguls, but you have to be super forward and drive the tips of your skis down the backside on all moguls, especially big ones. By being patient, I just mean don’t let your feet get out in front of you and cause you to be backseat as this is a fairly common problem. Wait for the bumps to come to you, don’t throw your feet at it defensively! You probably know how to use lots of range of motion, just really use as much as you can and try to get a good, early knee roll. I know you said that you get going to fast, but if you take more of a direct line there will be less “bucking” and less ruts so it will be easy to ski smoothly and stay in control; in this case, just use your carving and absorption to slow you down.