Watching people twisting the needles makes me crazy!!!! After break in the only time I fool with A needle is when I change prop sizes or there is A BIG weather change.
By big weather changes I mean like now, high is around 100 to 108 then comes winter it will get into the 30s, that's A big change and I have to fatten up my high end by 4 clicks. How do I know when?? My engines will go dead stick on me or just start running different, they tell me when it's time. Soon as it starts warming up again I start leaning them out again, it isn't much but those 4 clicks makes A big difference.
Most of my glow engines are 4 strokes, the 2 strokes seem to take the weather changes A little better.