So glad to see fellow ski addicts! You are starting where most of us started...open water, fighting rollers, trying to figure out speed, best boat path, etc. I spent several years doing the same thing between going to ski school and getting spoiled by good conditions. A little larger ski is just right for the conditions you are skiing in. Try doing some lean drills to get the feeling of being stacked, with your full body weight leaning against the rope. You can do those drills even when the water conditions are iffy. Then you can translate that feeling to doing the same behind the boat. I spent a winter leaning on a handle in my gym and the following spring, I was finally able to do it behind the boat-the magic "work zone". Also, make sure your driver holds a completely straight line when you are cutting...I once had a driver say that she thought following the shoreline constituted a straight line, and it looks like your driver has the same theory. It's hard to make a confident cut when the boat turns, even slightly in the middle of it.