IMO, the only "spot" that makes sense is the spot your stick is pointing at. This is the only spot that is parallel to the stick. You pick a corresponding spot on the OB, or on the cloth if it's away from the OB. The spot can be a light reflection on the ball, or an inlay feature on the ball, or a shadow on the cloth, or a piece of lint on the cloth, or a divot on the cloth, etc.
This is not an aiming method, because it's not telling you how thick or thin to hit the ball for a given shot and intended CB position play after the shot. You need to know that based on experience. But once you know that, this method's purpose is to keep your eyes parallel to the stick direction, so your eyes don't subconsciously throw your stick crooked mid stroke.