I have the engine, but have not run it yet. Manual is fairly un-enlightening, has nothing to say re: high speed needle, other than to break in rich. For idle needle, manual says open the throttle, look into the carb throat, screw in the idle needle until the point is "level with the nozzle." From there you break in on zero nitro, 20% castor is their recommendation. When engine will hold WOT without sagging, and idle needle has been tuned for smooth transition from idle to WOT, then OK to fly. Prop size 13x6 to 15x6. Other threads say nmt 5% nitro. I plan to break in (sometime in the next few weeks, time permitting) on pure castor lube, then transition to 80% synthetic/20% castor. Morris Hobbies is the US distributor, I believe. Their website may have manual download.