RE: Nock vane proplems with drop away...
There is no doubt in my mind that your fletch is hitting something. I too would try to shoot with the cock feather up to see if you get better clearance. However, I feel your rest is not dropping clear in time. I like for my drop-aways to pick up on the last 1.5-2" of the arrow when drawn, that way there is no chance of a fletch contact unless it's out of tune.