Running motors blubbering rich is old school.
Not for ringed engines, though built to higher tolerances they still have a lot of friction when new. Running rich enough to four cycle ensures that they will not overheat and wash's out the initill wear. Also heat cycling does nothing but take up your time. Unless overheated the engines ge nowhere near the temperatures to heat treat or temper the metals. Just run a tank at a strong four cycle, and another starting out at a rich two stroke and lean it out a click or two every so often. Then adjust the mixture and install the engine. Fly and have fun. Don't mind the 101 ways to break in an engine, you will just get confused over something that has no value.