You can look up the tiller sections in the "Classics" section for a good read. Like JParanee, even tiller for 3 under and 1/8"positive for split finger, (top limb distance greater than bottom), generally works for me.
Like most things in archery, you may need a little fine tuning to get the optimum setup for you.
Standard in the past was more like 1/4" positive, which works for me. What works smoothest is individual, depending upon such things as finger pressure and relative strength of the two limbs. Smooth, quiet and vibration free is the goal. Your bow will tell you. - lbg