If you go by the manual, once you set the TPS for 0 degrees (w/butterfly on throttle body completely closed), you then adjust the screw that opens the butterfly on the throttle body to a specific degree setting and leave it, do not adjust it again. Then adjust the screw to open the butterfly on the other throttle body to get balance close. I count the number of turns it takes to close it, then reverse to get close. Then start and adjust that screw for throttle body balance in mid to high RPM range. Then for low RPM balance, idle speed and CO adjust, use air bleed screws along with idle trim in the ECU. I use a TechnoResearch VDSTS with a laptop for degree settings, RPM indication (more accurate than tach) and CO trim adjustment and a Morgan Carbtune for balance adjustment.