With the glue-on nocks I use on my 2315' s, setting my nock at 5/16" puts my arrow just a tiny bit over square. That' s where I' d start for a release. For fingers, I bump it up to 3/8" , then I do my tuning adjustments from there.

Just never go below square. If you have to do that to get good arrow flight, then your tiller is out of whack and needs to be reset.