I'm going to most likely be balck listed for say this but... Don't move your arrow rest to fix the bare shaft. It is wrong to do this. A bow is tuned when it shoots a bare shaft perfect, when the bow is centershot. Paper and bareshaft tuning tell you the spine in relation with the arrow rest. A bow will bareshaft tune by moving the rest however you will have adverse side affects. I can prove this. Take some arrows that are out of spine for your set up. Move the arrow rest to shot the bareshaft perfect then shot an arrow at 5,10..30 yards and look at how the point of impact changes left to right. Your arrows will not be in a perfect line. Those of you that move the arrow rest really need to look into how you are tuning. This is all my opinion, but moving the rest is a bandaid fix.
For the beginning process of bare shaft tuning I'd agree with you. If your arrows are impacting several inches to right or left then fix the problem with arrow spine (I also adjust bow poundage like mentioned above).
For the end process (if neccesary) then I'll move the rest to get exact impact (I'm talking micro adjustments here) between fletched and unfletched.
I'm a little curious how you know you have "perfect center shot" by eyeballing or measuring for that matter?[&:] Thats what those little micro adjustments are intended for on the rests. When all is said and done with my setups and both fletched and unfletched shafts are impacting the same (especially after moving the rest) then I feel I have accomplished a more true center shot than I had to begin with.