You adjust the float by bending the float tang, which is the bendy bit that contacts the float valve needle from the underside of the float main tang. Best method is to stand the carb assembly on end, facing across the open float bowl (vertical). Tilt the carbs so that the floats just makes contact with the valve needle without compressing it. Then you measure float height from the lip of the float bowl/carb body to the bottom of the float. Make sure it is the same height measured at all points of the float, not just the end or middle. You may have to adjust the floats for 'trueness' from the main tang, which the adjust hangs from. It's important it is neither restricted in range of movement, and that it seats evenly.