I have two OS .46 AX's. Wasn't all that much to break them in. And basically, once you set the high end needle a few clicks towards the rich end at max throttle, you never really have to fool with it. I run both of mine on Byron 10% fuel....although I may start using 15% (the green color'd stuff). I also run an 11x6 prop on them. They are about 20 bux more than a TT Pro and Magnum but OS has just a tad bit more quality built in.

Dave...