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ROFL it's Waffle
yeah I've read a LOT about break-in, and it's easy to be swayed one way or another because both seem to have pretty logical reasoning. Honda once posted a video about how they did their break-in of the latest generation NSX and why they choose to do what they do. A hard break-in is definitely not part of their process, and the reason behind that is that the combustion pressures are more than enough to seat rings. The higher the load, the more hot spots are formed on the cylinder walls by imperfections, and hot spots will wear rings down unevenly. The best thing to do (according to them) is to scrape these imperfections "gently" to avoid hot spots for the first few hundred kilometers. Once that's done, the engine can be driven harder and harder until break-in is completed. And that's for a performance engine in a sporting/performance application, designed for aggressive driving and racing.
There must be a reason why literally every car manufacturer recommends breaking in gently vs hard break-in. I can't say that car engines are the same as 2-stroke snowmobile or 14k rpm bike engines, but I would tend to follow a more varied rpm (gentle) break-in, no idling, no traffic driving, no highway driving and as little time spent warming up as possible.
I've read a lot about this, but I guess until I see 5 identical engines broken-in in different ways and then dyno'ed before and after, and torn-down, then I'll believe it. Until then, I'll follow manufacturer's recommendations (pretty closely, but within reason).