SET THE TIMING FIRST!!!
Then warm the engine up FULLY to operating temperature.
If these are a 'ways off' the idle speed will change. If it changes much, "diddle" the idle speed to keep it inline, so that you are making final mixture adustments AT THE idle speed you want
I would not turn them in and back out. I would start with "what you have, and just "ease" them in until you see the gauge start to drop. Then back them out both a bit at a time for "max" vacuum. Then last, just turn them in "just a touch" until the vacuum "just does or "just doesn't" drop