The problem is "what is parallel". SME has the perfect answer on the V with a horizontal line silkscreened on the arm itself, however, absent that line with other arms, its all listening and evaluative. Fremer suggests that a microscope and computer program be used to determine the angle of the stylus...a very complicated and exhausting effort. For me, there really is no answer...I set my arm that has a significant tapper so that the bottom of the arm is going uphill a bit. I am confident that I have not coaxed the ultimate sound from this adjustment, however, I am also confident that I will never be satisfied and have to restrain myself from tinkering my life away on this. I love the sound of my setup and just have to be satisfied with it until my unrest that "maybe" I can get more from the arm" will overcome me yet again....yet another disorder I have to suffer from.