Here is the official spec I found in the factory manual or someplace else. You don't have to follow it exactly.
Idle adjustment: 1/2 Turn from screw stop lug
Idle mixture: 3/4 Turn then in or out from there for highest RPM. Then adjust idle screw for correct RPM.
I'd start with 1 to 1.5 turn on the mixture screw and enough turns on the idle adjustment screw to keep a high idle. After everything is warmed up start doing your fine tuning to your liking.
Make sure that o-ring is fresh as that is what I find causes an erratic idle. Any o-ring is fine. I think mine came from a Harbor Freight assortment or the Home Depot hardware store. Also find any vacuum leaks around the intake manifold gaskets, recirculating gas fittings or anyplace else you can think of.
Engine tuning can be frustrating and time consuming. Took me a year to finally check my o-ring on the mixture needle when I had problems on a car with an erratic idle. Don't be afraid to drive it, just keep doing a Heal & Toe to keep your engine running.