Kevin Cameron writes the technical column for Cycle World plus some technical articles there. His writing always makes lots of sense to me so when he wrote about break-in I paid attention.
Kevin says that the best break-in would run the engine hard enough to generate moderately high piston forces (to seat the rings) but not so hard that the oil fills up with metal particles. In olden days, machining was not as precise as today and new parts would quickly wear together and put lots of metal particles in the oil. With modern machining, engines go together with smoother parts and closer tolerances than before. This mostly eliminates the worry about overloading the oil with particles. This frees the break-in period for seating rings.
What Kevin Cameron wrote makes sense to me and it matches your break-in plan (and Motoman). I am suspicious of many claims I read on the Internet. I have written books and magazine articles so I know that isn't a guarantee of "fact" either. But my long reading of Kevin Cameron has led me to trust his mechanical chops.