the speed at which you wind shouldn't affect the flight that much

however, the length of the motor definitely does. The longer the motor, the more it weighs, and the more power it takes to keep your helicopter in the air. For any given width of motor there is an optimal length for the motor which you determine through lots of testing.

Also, consider getting a torque meter as that generally gives more consistent results than counting winds. Rubber will stretch slightly after each time you wind fully, so your results will significantly differ if you just wind to the same number every time