The SS40 is a plain, cast iron piston with a steel liner, and should be broken in as such. You guys are right in the fact that ABC engines need to be brought up to temp for proper break-in, and that too rich of a break-in will cause unnecessary wear. However, this is not the case with the SS40. It should be broken in with a slightly rich setting, just about breaking into a 4 cycle. Alternate between 3/4 throttle and idle. Then, after the 2nd to 3rd tank start to lean it out a click or two at a time. After about an hour of running, turn the needle in until you hear the peak RPM at full throttle, then back it off about 1/4 turn. The first 2 to 3 tanks I would do on the ground, after that you can put it in the air.
Enya engines are made to very tight tolerances, proper break-in is critical. Many people are impatient when it comes to breaking these engines in, and they break connecting rods. If you are patient, the result is an engine that makes good power and will last a very long time. I hope this helps.