Unless the carb synch is massively off you should still be able to get idle at near spec. Adjusting the synch at very fast idle or with enrichener opened will get you less than satisfactory results. I usually think of carb balance as the 'finishing touch' on bike that already runs OK. You may want to redo that eventually. However, from your description it sounds like you may have some residual contamination that has found it's way into your pilot jets/circuit.
You're probably gonna have to reclean the carbs...but here's a 'quick and dirty' you can try. Remove the mix screw, spring, washer and oring from each carb. Drain and remove the drain screw from each carb (both done without removing carbs from bike). Take a good fresh can of carb cleaner, put the tube into each mix screw hole as far as it goes and give it a good flush. Put a rag under the carb to catch the carb cleaner that comes out the drain (sometimes it's hard on the engine paint) Reinstall all parts and give it a try...first start you might want to hold throttle half open as the carb spray will have flooded the intake manifolds. Sometimes this works if the slow circuit contamination isn't really stubborn.