The main concerns while breaking in an engine is to get it up to operating RPM and temp. Being tight it will tend to want to run hotter so a slightly richer setting is required. To get the RPM up in the normal operating range you need to lessen the load with a slightly smaller prop. Running it overly rich will keep the temps too low, you want all the internals to expand to normal operating tolerances. Do not run the engine on the ground at full throttle for a long period of time, it will get overly hot and injest dirt. With todays manufacturing processes most engines do not need a lengthy break in. Run one tank on the ground cycling the power from high and low. From there you should be able to get a reliable idle and transition. Go fly the engine at a slightly rich setting. Over the duraration of the first gallon of fuel you will notice the need to slightly lean the low and high speed needles, it will also start using less fuel as well.