It seems like your new rockered board does not track the slope as well as your old camber board when carving. What you need to do is have more speed and lean more to make a tighter carve with your new board. You need more weight on the edge so the full edge engages the slow and that will help you make sharper turns. If you do not have enough weight on the edge, then the board will slip out or you will rudder.
To have more weight on the edge, you can lean more. But you also have to have more speed. One suggestion I have for all riders is to be more aggressive and active with your legs. Go fast but be ready to hold the g-force as you make a sick carve (or do a full stop if you're out of control). Also if you are on steep hill that is bumpy, it's acceptable to not be able to carve elegantly. You need to have loose legs when absorbing bumps, but when it's well groomed you need to be ready to hold down the power with your legs.
I'm not really good with terminology and I don't think people can learn a sport from a book anyways. What I suggest you do immediately is committing to the speed. You will be able to do this after you become confident throwing a big aggressive full stop at will.