Wouldn’t “tilting” the carb forward using the slot “lean” the fuel (no pun) and tilting backwards be richer setting? The floats are on a fixed axis and the jet is centered. Seems for instance tilting all the forward would move fuel to frontal part of bowl and when the slightest amount of fuel ALSO TOUCHED back float it would begin the process of shutting off fuel sooner then if the carb were level. And opposite for backward tilt.