hogflyer

10% fuel is fine, and what I fly in a couple of my engines.

One way to tune your engine is using the pinch method. Go to full throttle and pinch the fuel line briefly. Does then engine speed up, slow down or stay the same?

Here's how I set my engines when I'm not using a tach:
I'll go to full throttle and turn the mixture out a bit to make it rich, then lean it until I hear the RPM's peak and want to start to drop. Then I'll go 4 clicks rich and use the pinch test to double check (I usually pinch the fuel tubing about the middle of the cylinder):
Engine speeds up slightly when the fuel line is pinched: It's slightly rich and OK to fly.
Engine slows down or stays the same when the fuel line is pinched: It's too lean and needs a click or two richer on the mixture setting.

Another thing you may want to look into is the Eagle Tree 2D/3D Stabilizer. I have one to try on a trainer (Kadet LT-40) but haven't hooked it up yet. Guys I 've talked to who have used it say it works great. You can turn it on and off - fly with it off and if you get into trouble turn it on and let it recover your plane back to level flight. They've used it on windy days to shoot landings and say it keeps the plane in a level attituds to the point they use throttle and rudder to adjust the approach path. Besides being able to turn it on and off, you can also adjust the gain while in flight. But it does require at least on extra channel to turn on/off, and a second extra channel for gain adjustment.

Hogflyer