Tail down pertains to vertical tracking angle..that is, looking from the side of the cartridge while its on the record, between true horizon and the angle of the cartridge - presuming the stylus was put on correctly by the cartridge maker. Verical tracking angle or VTA will change with the VTF (verical tracking force, or downward weight of the cartridge) and/or by raising or lowering the height of the arm. Tail low means the arm is to be adjusted a little lower in the back so that the cartridge rides tail low. The quesion hera is how much, and you adjust that by ear. I, first adjust the downward force of the cartridge to a little bit heavier than the center range suggested by the manufacturer. Your VPI has the capability of adjusting the height of the arm while the record is being played if done carefully. I would start with the arm being perfectly horizontal. I do that by taking a lined index card and folding it in half so that the lines on the card are horizontal. Carefully match the edges of the card, so that the lines are indeed perfectly horizontal. Put the index card between the arm which is on the record, and the spindle - very close to each other. The platter should not be spinning. Get down and eyeball the line on the index card that corresponds to the horizontal line of the tonearm. If the tonearm is not exacly horizontal, use the very front to the arm to decide which line on the card lines up with it. Mark that line in pencil. If you notice, there is a notched thumb wheel around the pillar of the tonearm. Turn that notched wheel so that it is firm against the bottom of the turntable. There are 2 allen screws at the base of the arm..one on the right side, and one in the rear. When these allen screws are released, the arm will be resting against that thumb screw. By turning the thumbscrew, you will be raising or lowering the tonearm. After turning the screw a couple of times, use that index card to see your progress..if the back of the arm is going up or down. Continue to adjust the arm until the arm is perfectly horizon and parallel to the marked line on the index card. Look and align with your head at the same plane as the arm/line on the index card to eliminate parralax errors. Once the arm is horizontal, remove the index card, turn on the turntable and play the record. By turning that thumb wheel, you can lower or raise the rear of the arm/cartridge which adjusts the VTA. Some, listen for the quality of bass. I adjust for maximum air and depth. I had to play with this adjustment many times, over many days to hear any change at all. When you learn what to listen for, you can adjust that VTA until the sounds kind of snap into focus. When you are satisfied, tighten the two allen screws at the base of the arm, and you will hear a big improvement again. That index card will enable you to repeat your setting, because if you really are after perfection, 200 gram records need a different VTA than the 180 gram records, etc.