There really is no such thing as a run in fuel. There are a few brands out there that have a so-called "special break in formula", but you should really break in the engine using whatever fuel you intend to run through the engine on a regular basis.
You can go with what the manufacturer of the engine recommends or you can use what you have in relatively decent supply at your LHS. Your call.
There are as many opinions about running in as there are drivers, but I just use my regular race fuel with 16% nitro, and 12% oil. Just make sure you run it rich the first tanks, and I think you'll be ok.
Why does everyone run 10% fuel? I have always have MUCH BETTER luck with 20% fuel. Performance and tune wise. I dont even stock the 20% at the shop. Just about everyone I sell a 20% quart to will agree that its a lot better then the 10%?!
Runin fuel.... Questionable at best. A new engine I will open that HSN untill she is so fat she wants to die.... Back in 1 hour on a clockface and go at it from there. The BIGGEST thing to watch is the TEMP when you get the new motor.
Keep that thing within norm Temp ranges at ALL times!!