I've been thinking about this a bit what since buying a new blade. I think always let it warm up. And not to labour it too much. I'm not going to go exploring the rev limiter for a good while I don't think. That said I think I'm going to using most of the rev range after a couple of hundred miles.
It's not the rpm who makes the correct run in, but the throttle apply...... For the first 500 miles, you can't stay over 10 000 but you you can go with brief roll on, and the more important it's to apply SHORT but STRONG throttle ( quick and strong just few second, like 5000 / 8000 ) and never below 4000 rpm, too low in the rpm. It's with strong and short throttle an engine run in the best
Pretty much what i did with mine too now on 36000 and have never needed to top up oil between changes