Ed,

Don't be apprehensive about making further adjustments to your motor. Just make note your semi-reliable starting point so that if you go too far either way in your adjustments, you can return to what you had. Keep the increments of adjustment small and observe the changes in the engine's behaviour.

A tachometer is also helpful. If you are trying to idle below the manufacturer's idle setpoint RPM, you might always have an unreliable idle, and no amount of mixture adjustment will fix it.

Glad to hear your plane made it past the first flight.

Dave