I was only making sure it didn't seem like you wanted him to run his engine in 2-stroke mode during the entire break in period. You did not say to run it in lean. However I don't think it's accurate that you should not run it in 4-stroke mode at all during break-in. You're right in that no one says to run it in 4-stroke mode constantly during break in, but they do say to run it in 4-stroke mode half of the time during break in, the other half in 2-stroke. If it is run in 2-stroke mode all the time during the first couple of tanks, it will get too hot.

OS 46FX instruction manual states:Run the engine for one minute with the throttle fully open, but with the needle valve adjusted for rich, slow "four cycle"operation. Now close the needle valve until the engine speeds up to two-cycle operation and allow it to run for about 10 seconds, then reopen the needle valve to bring the engine back to four cycle operation and run it for another 10 seconds. Repeat the procedure until the fuel tank is empty.

That's all I was going by. It seems you need the best of both 4 and 2 cycle.