Round side faces up as you look at the carbs oriented on the bike.
so the flat sides are in the bowl.
measure from the gasket rim, to the highest point of the flat side. which is likely to be the point furthest away from the float pin.
be sure its not depressing the float valve spring. just resting on it.
set at 22mms, but if still rich or overflowing set at 24mms
i've had the best luck with 24mm.
the goal is to get the fuel level at 4mm's below the gasket seam level.