Zulu,
The most forgiving state of tune for conventional bows (not super stiff torsionally or super fast) will have the fletching clearing the rest at 1.25 oscillations as well as impact the target on the central plane. As the string comes off the fingers it is deflected outward and continues outward for a little bit. Peak outward deflection would be considered 0.25 oscillation. The string and nock then wag back to the central plane at 0.5 oscillation, toward the sight window at 0.75 oscillation, and back to the central plane at 1.0 oscillation. 1.0 is also about where the arrow should come off the string. In a perfect state of tune the arrow bends out and around the bow at 1.25 oscillation and will continue to do this even with less than perfect releases (to a degree). Basic tuning will have the correct arrow spine, length, point, and fletch set up for a given bow and brace height. If you are grouping ok, and the fletching is not hitting the riser you are good to go.
Precision / fine tuning requires many cycles of testing small changes (BH. nock height, nock fit on the string, tiller, center position and spring button tension and on and on) and is only possible to the degree of skill that one shoots. Shooting many groups for score, make a tiny change, test again, and so forth.
Sam is correct about center shot setting being more critical for conventional bows. All the talk here about starting at center setting comes from those shooting really fast and stiff bows. With bows shooting over 210 fps (many are shooting over 220) there is simply not enough time to get the perfect 1.25 oscillation clearance. Folks with these high performance bows are shooting 1 plus stiffer spine, using minimal fletching, center shot setting, and clearing the bow with a lot less to spare. I have seen some high speed footage that look like the arrow is just barely making 1.0 oscillation as it clears.
HERE is an article by Dr. Lieu at Cal Berkeley that goes into much more detail. I spoke with Dennis Lieu about high performance bows and clearance issues at the recent Cal Archery fundraiser shoot. He is planning a followup for the article as soon as they get a newer high speed camera.
All the Best,
Rasyad