A two plane swing requires you to actively cock your wrists. With a one plane swing the weight of the club tends to hinge your wrists back naturally and making the swing less complicated.
Have the clubface aiming where you want the ball to end up and take your stance aiming at where you want the ball to start off, and then swing on your stance line
Eliminate the term weight shift. It is actually a move to the back leg and then a shift to the front leg. This allows for natural head movement and body rotation