I have never measured mine but I use a jo jan multi fletcher and the clamps have a notch in them and thats where I have always set my fletchings, I would guess it is around 1"+or-...I am not sure as to what is the better position but if yours fly better closer to the nock then you might have answered your own question. I am sure that there are some guys here that know the answer and I too am interested to see where this goes...