Here is what they tell you about using a hobby knife to set tweak " after all your chassis adjustments, find the center of the front and rear of the chassis and mark it somehow. Then set the car down on a flat level surface, but make sure you can see your marks on the chassis to find the center. Take your hobby knife blade and run it under the rear or front of the car where your center of your chassis marks are at and then tilt your hobby knife up slowly until the tires come up off the ground. When looking level with the table you happen to see one tire lift off the ground before the other then your car has tweak. While looking at your car (with the front end towards you as an example), if your right tire (which is actually your drivers side) comes up off the table first then you would need to put more pressure on the left back shock (which actually would be the passenger side) or take pressure off the back right (which actually is the drivers side of the car). Then flip the car aroud and do the same adjustment for the rear of the car.