I'm using a Menz 18x6.

I wouldn't waste time or fuel "running it in" as you say. Follow the directions and keep it rich for a while. After that first 5 minutes below 5K RPM, run a few tanks in the air doing pattern type flying (big loops and cuban eights) and then after a couple gallons (which won't take long!) think about leaning out the low speed to get better fuel economy. Watch the high speed doesn't go lean when you punch out of hovers and you're engine will reward you.