Hi Wilf,
One of the big inputs to shortening break in times for modern engines etc has been to wash the components during manufacture. They are washed very precisely and the 'waste water' is particle counted and then filtered. this has been a major contributor to extending the initial service period,
oil change etc. It may not answer your query directly but plays a part in it. Personally I always like to run a new motor in gently, especially when the moving parts are very close to my body and there is potent horsepower to help hurl them at me.
Charlieh