I have found that for my old Bear bows (I have 4 that I shoot), which are tillered for split-finger shooting, that I have to do a little tinkering to get them to shoot at their best using three under. I raise the nock point up to about 3/4 inch and raise the brace height just a touch and the bows seem to tame right down and perform well.
Have fun with your bows.
Joe