I've been experimenting with different finger positions, after realizing a lot of my left-right errors were due to fingers and how they release. First I noticed that my index finger is set lower on my hand than my ring finger, so even though they are the same length the joints don't line up. There's no way to put 3 fingers on the string all in one line, for me. Two fingers (or points) define a line, it's harder to get a 3rd finger (point) on the same line. When one finger joint is out of alignment with the others it pulls the string, left or right depending on which finger(s) have the most pressure.
I was talking to DamascusDave who said he would shoot with just one finger if he could, and that some of the best Olympic archers put 90% pressure on the middle finger and almost 10% on the index finger, with the ring finger barely touching.
I tried that but it was too much pressure on the middle finger, made my finger tip numb.
Then I was looking at a photo of Glenn St. Charles shooting, on the back cover of one of his books. He's shooting split but the ring finger is extended, perhaps barely touching the string, and certainly not wrapped around it. So I thought, he's really shooting with two fingers. I tried using only the index and middle finger split, with the ring finger curled up and not in use, and maybe 40% pressure on the index finger and 60% on the middle finger. So far that's working great. With the right glove 2 fingers is plenty to take the weight of the bow, and there's less variability with the fingers. Who says we need all 3 fingers to shoot? It's not a rule.
But I'm still trying it. I've heard you have to shoot 1000 arrows before a new technique is perfected. I have about 850 arrows to go. For people trying split, 3 under or whatever, I think it takes a long time to tell if it's working.
Plus I've realized it's not all in the fingers. Often what I think are release errors due to fingers, are actually errors of not pulling the elbow all the way back with the back muscles, and then just relaxing the hand to release. Then again it could be a loss of focus. It just takes a moment to lose focus and then the arrow goes far off target. The fingers get blamed but the problem is in the mind.