Found the following article on Model Sport Aviator
http://www.masportaviator.com/ah.asp?ID=41&Index=0

It presents a technique for idle adjustment I had not heard of and seemed to be a little more precise than watching the transition from idle to WOT.
I have been holding off full power needle valve adjustment until I had broken in my engine some. I might try this next time I'm at the field. I have not been able to get my idle much below 3000. According to this method, my problem is likely that my mixture valve is still too rich. (The engine loads up and stops below a certain RPM that is higher than the 2400 RPM target laid out in the article).