Here ya go:
Its sometimes a bit different than what you would think and also keep a look out for what the humidity and temperature are.
When you tune your motor and you find the sweet spot and say ok its tuned. That day, go inside and check the weather in your area and record the temp at what time and the humidity. That way the next day, month or year you can check out how it was set on whatever and compare that days humidity to the current and adjust accordling.
Or if your having trouble you can always reference it.