breaking in a motor just means seating the brushes so the brush face sits around the comm nicley. It wont reach its full potential until the brush is seated properley.
I only run Mod, but I use a trinity timming jig/break-in stand, it has a timing guage which is more accurate than the sticker on the motor, also you just clip the fan that it comes with it on the motor and I power it up at 2 volts for 4 Minutes, then 3 volts for 1 more minute (at zero degrees timing, I also tried 1-3 degrees to lower arking but it only seemed to make things worse) and set the timing I'm going to run and Done !! ready to race.
Mugen MTX & MRX
"He who dies with the most toys wins" - Phil Harris