Don't know what the carb looks like but most of the carbs that have the High speed spray bar coming half way across the venturi, require the tip of the low speed needle to be about .020" from the end of the spray bar at full throttle.

Some of the ones that go all the way across the venturi have a cat eye shaped slit on the engine side. This idle needle should be half way across the slit at full throttle.

There are other variations