The way I see it is and my voodoo logic..Wear a motor in with no load is bad on rings. Why because its critical at this point in juncture for the rings to establish a good even trained wear pattern. With no load on the piston rings they would be more pron to simply chatter as the piston travels up and down. So just idling the thing and revving it would be a bad idea under this logic.
You got's to ride it.
After a break in period this wear pattern is established better there for less erratic chatter per say as the wear pattern has train in and established it's course correctly or is what it is.
I like to do my first good run on a sweet steady 4 mile long or even longer hill. Doesn't need to be vertical.
Just a nice steady incline. ''A steady load'' Last I don't really pamper my motors ether. I ride it like I expect it to perform for the most part!!