I have heard alot good things about Bitz jigs. I was looking at them and noticed that it comes with several nock receiver options. It comes with a standard three fletch at 120 degrees but you can also purhcase what they call a TM three fletch at 120 degrees with cock feather down. What is the difference and are they necessary? I use super nocks and do not glue them to my ICS shafts. Therefore, I can turn and adjust them so I can put cock feather down if I like. Besides, I have a drop zone rest and clearance should not factor. I don't need a cock feather. Am I correct or way off base? Thanks Again.