I too, am having issues with nock high. I am bare shafting using CE Heritage 29" 400, GT Trad 29" 55-75, 29" GT 35-55. I have been changing the spine using 125, 150 and 200 grain field points. I can control spine left to right aka stiffness and weakness. What I can not eliminate is the nock high flight. I have moved my nock from .75" to .25". Moved my cat-whiskers up and down at all heights on the string. I have not played with the shelf but will try that next.
The question is: What should I look for with in my form or release that could be causing this issue? I believe that I have consistent form. My release is to pull through the shot, hit anchor, release and then touch my shoulder. When pulling back; I pull with my middle finger first. I am shooting split finger.
Thanks!
Martin