Preset the tang on the float setting tool to the desired height (the standard setting is 20mm to the raised rim adjacent to the gasket surface). Set the tool's width just wider than the width of the floats. Orient the carburetor so that the float tang just touches the needle's spring-loaded plunger, but does not depress it. Hold the float height tool onto the carb body, making sure it is square to the gasket surface front to back (side to side is taken care of since the tool straddles the floats) and so the tang lines up with the point on the float that is farthest away from the body. The tool's tang should just touch the float but not depress it. Flip the tool 180 degrees to check the other side of the float. If the other side is different, correct the twist by bending until they are the same. Set the height by bending the float tang with a small screwdriver.