When putting nocks on arrows, should the nock be aligned with respect to the leading edge of the cock feather, or the trailing edge? Or should it be set right in the middle of the helix? I shoot both off the shelf with a recurve and thru a whisker biscuit with compound. I shoot feathers mostly(5"), but also have some helical vanes. The feathers have a pretty good twist (helix) on them, so it does matter.