Of course how you release the string will have some to do with your best nock locator position.
This is one of the easiest things to check and adjust. I paper tune. Put newspaper, easel pad paper, wrapping paper, etc. taped or clipped to a frame (open ended cardboard box, picture frame, or special PVC frame). Frame could be about 24"x24". Set it up at shoulder height and shoot from about 6-8 foot away. Make sure your backstop is at least a complete arrow length from the paper.
High tear, lower the nock locator. Low tear the opposite. Move the locator about 1/16" at a time.
I shoot 3 fingers under. I always start at 5/8" high. I rarely have to adjust. I've owned and tuned 3 widows; PSA, PCH, and PA.