OK, your method of breakin is something we would NEVER do. We start engines and drive them. We accelerate up and down our parking lot with a rich setting. The engine usually needs the battery kept on the glow plug because the idle mixture's usually too rich. We accelerate up and down, up and down. We'll gradually lean the high-speed needle a bit at a time as we go. At some point, we'll be able to remove the battery from the glow plug and get an idle mixture adjusted. We never run the engine so that it's 'blubbery rich' when it's at full throttle, but we make sure it's always rich of peak RPM.

Many methods popularized by R/C car operators to "break in" their engines will do nothing for engine life. We know people who won't run them over 1/2-throttle, some who idle for 2-5 tanks, and so on. These methods may work for racers who only need to get their engine through a racing weekend, or even a few heats or a main, but they won't break your engine in for longevity. Using a heat gun to help start it the first few times won't hurt a thing, but the engine needs to be driven.

Your engine is of ABC-type construction, and MUST get up to operating temperature to properly break in. It needs to be run. If we could, we'd put a prop on it and break it in at full throttle, keeping it in a rich "2-cycle" mode, and gradually work it towards peak RPM over the first 40-60 minutes. On a car, we accelerate it up to full and back down only because we run out of room. Fuel must contain at least 18% oil content to make sure the engine gets enough lubrication.

As far as needle settings are concerned, we're not negative. All engines, whether for cars, airplanes, helis, or boats, have suggested starting points. You will then adjust as necessary from there. We always start out with high-speed and low-speed needles set much too rich and go from there. That's just how it's done. The suggested starting points are not where you'll wind up running the engine, but are just places to set the needles. O.S. could just as well told the user to just make sure they were very rich and be done with it, but people want specific numbers. Please remember that these are alcohol-fueled engines, and that means that the needle settings will change from day-to-day as air pressures and temperatures change. They will even change significantly from a cool-dry morning to a hot-humid afternoon.