If you start overly rich, you will see the rpm's increase as it leans out. If you go from lean to rich this will not happen. You will going overly rich then have to come back. I stand by the what said about the needles not being the same also. No needle and seat are the same. We are talking small differences here. The full turn was just an example.
I believe you're mistaken about the idle circuit. It draws fuel all the time. That is why it is important to get it right before you adjust the primary and secondary circuits.
There is always more than one way to do things. If you don't have a vaccum guage, you can use just a tach.