I'm in the prosess of rebuilding my motor. I have a few Q?

[ATLGt]

Actually, over breaking in can glaze the walls of your block and cause blow by later on. Especially with a positive pressure engine.

[WANTED]

I'm not a big fan of Royal purple. I played with it for a while, and found it couldn't maintain that extra horsepower for very long. By preference, I use Mobile 1.

Break in is funny. There are two schools of thought, break it in hard or break it in gentle. Same thing applies to bikes. In either scenario, if the engine is going to let go, it will plain and simple. No amount of gentleness will prevent that.
Yes, all major manufacturers do say take it easy for 500+ miles and don't go over xxxx rpm, but there are two reasons for that. The first one was stated above, to cover their ass. Most people don't know how to properly break it in hard. The second is to allow the driver to get acclimated to thier vehicle. Sounds funny, I know, but some people can't get used to a new car right away, and if it's a dramatic jump in power than they're used to things could get ugly.

I say, take it to the dyno, run it thought the RPM's, and then drive it as you normally would.