My brother and I pretty much agree with the "leave it alone" theory.

The low speed needle, or air bleed screw, hasn't been touched on any of our engines since right after break in.

Our OS four strokes, and all of our two strokes, seem to tolerate a lot of weather change without needing adjustment. If they sound good and transition well we do not tach them.

Our Magnum four strokes get tached before the first flight each time we go out. For some reason they seem a bit finicky to needle settings. One click, either way, from ideal seems to make them very rich or very lean. Once adjusted they are good for the whole day.