I love bareshaft tuning. OL Adcock has a good section on it

http://www.bowmaker.net/index2.htm

Basically, you shoot 2 bareshafts and 2 fletched. Note where they hit in relation with each other. If you bareshafts tend to hit right, then your a little weak.If they tend to hit left, your a stiff. For a weak arrow, lower your point wieght, or cut down your arrows some by 1/2" at a time. If your stiff, increase point wieght. I want my arrows slightly weak. That way when I put my feathers on, they should be perfect. Also, in a tree stand if one has the tendency to short draw, it will not affect fight as much. Arrow spine adjustments are sensitive to you a crisp release. This is the one reason, I wouldn't recommend it for new archers to finger shooting.

Bareshaft is really good for vertical nock point adjustments. If you bareshafts hit low, your either hitting your shelf (too loo nock point) or too high. I like to start my bows out high and slowly move down until my bareshafts hit perfectly with my fletched arrows.

Follow up your bareshaft with broadhead tuning. And maybe paper tune. Also shoot your arrows 30 yards and notice what they are doing. If all the stars line up, your set.

I discussed this with Bryon Fergonson, about his section in his book. And he said its all he uses. He explained its nice to carry some bareshafts, and make adjustments when on a hunt.