RE: Tuning: Adjusting Nock Position
You can get a "Bow Tuning Set" at walmart for less than $10. Not sure on the price but it was cheap. It has a square that clips onto your string. Put an arrow in and set the bottom of the square on the arrow. Then adjust the loop. I used needle nose pliers wrapped with electrical tape so they were not abrasive. It was very tight. After adjusting I pulled it once with my release and it tightened up very nice. Then I verified it again with the arrow and square and it was good. The set is just a square that clips onto the string and a pair of nock pliers.
Good luck