To get the right pressure get yourself a scale in your garage and get your machine on it powered off and press down so you can figure out the feel of the pressure of 9-14lbs on the scale.. You may be surpised.. Once you know what that feels like then try it again on the car using a 2x2 section. Dont move on till you figure out what it takes to correct a 2x2 section. Also make sure you mark a line on your backing plate with a sharpee so you know when you have the machine on you know the pad is spinning. Good luck and be patient. This is an art and your almost there..