@19skier I used to have the same problem until someone told me that I just needed to let the ski flow and let it ski itself around instead of forcing it to do this. I believe I was rushing and I was trying to force the ski round with loads of back foot pressure (ended up losing all of my angle and i found myself struggling to regain that angle I had lost).
I ski at about the same speed as you and I too do not use a wing because I don't think It has that much affect at the slower speeds and it teaches you to have a bit more front foot pressure in the pre-turn to help slow the ski down. If you maintain this front foot pressure or equal pressure on both feet the whole way through the turn and out of it you should notice a good deal of difference.
The objective is to find that sweet spot on the ski, which is a little more forward than where you are skiing on now. I agree with @mwetskier when he says that you are trying to slow the ski down by jamming your back foot down. this is not when you should be trying to slow down, you should be doing that in your pre-turn by shifting your weight a little more forward and maintain that balance point the whole way through the turn.
Try to apply a little more front foot pressure through the wakes as well which will help a lot to set you up for the next buoy.