Since your body is bent over more in the one plane swing the shoulder plane resulting from the body pivot should be pointing to the ground just outside the golf ball.
To develop a consistent and repeatable swing every club in your bag should have an identical tempo and rhythm, tempo is the rate of speed from start to finish of the swing while rhythm is the acceleration and deceleration of the golf club
The one plane swing requires that you bend from the hips more than the two plane swing set up. This move is counter balanced by your buttocks going back more, thus maintaining your balance on the balls of your feet.