2200 to 2400 is about as slow as I like. You may be able to get to 2000, but only if the engine is well broken in.

How far open is the HS needle? Backing off "a few clicks" may be too much. YS engines don't like being too rich on the top end, if fact, sometimes two clicks is too much depending on the fuel and weather.

Fuel running out the carb indicates that a piece of debris is holding the regulator plunger open and allowing the pressure in the tank to push fuel into the carb. Or it could be the plunger is sticking.

If it blubbers in the transition and barfs out raw fuel and a cloud of smoke when you advance the throttle, the reg is too rich. If it stumbles, with no smoke or raw fuel out the exhaust, it is too lean. Don't be afraid to run the reg in or out by a full turn if you have to.

Still sounds lean in the mid range to me.