System 4 allows a single-user or multiple users to finish both sides of a cabinet door at once. Rest the front side of the cabinet door on the four pins. Spray the outside edges and top, flip cabinet door while it is still wet, rest on the four points, and spray the top of the cabinet door. Once all of the cabinet doors are finished, rack them onto the drying rack. You will not experience marks because the points are just right, and you will never rest the door on the same 4 points. Do not recommend on pine wood.