I have a lot of experience tuning this engine (mine anyway). The high end on mine could not get rich enough to drop the RPM's 200. I could never get that to happen. It's common knowledge that the carbs can't supply enough fuel to get rich and drop 200 RPM's on the high needle. You'll see threads discussing this very issue. I'd scratch my words "all the way out" and use the words "2 turns out". You won't get into trouble setting it there. What's trouble is setting it too lean hence the reason for this thread (unless airflow was the problem). Setting the low end to what DA recommends is actually trouble. It will bog and possibly crash your plane from fuel build up at idle. It actually happened to Chris at Extreme flight. He had his low needle set too rich and almost cost him the plane. DA will not actually tell you the proper way to tune an engine. They just tell you some factory settings which are usually too rich on the low end. My friend and I can both attest to that on three of these engines now.

Edit: Well what do you know. The thread was in the the first page of this gas engine forum:

http://www.rcuniverse.com/forum/m_28..._1/key_/tm.htm