What do the instructions say ?

In any case, 2 1/2 turns out SEEMS about right. When you break it in remember to use the 2 and 10 rule - 2 minutes of running and let cool for 10 minutes. Do this for the first 2 or 3 tanks, gradually increasing the run time after the 1st tank. By the 4th tank you should be able to run the engine for the full tank.

I suggest using an OS #8 plug and whatever % nitro you plan on using in the engine. In "theory" the nitro content should not matter, but in the real world it seems that what ever % nitro the engine is broken in on is what it runs best on.