In your picture look at where the bow square is in relationship to your brass nock. See where the line on the square is level with the top of the nock? That line is even with the bottom of the blade that runs down square. Does this line and the bottom edge of the square represent the bottom of your arrow, the middle of your arrow or the top of your arrow?

If it represents the middle of your arrow then when you nock an arrow even if that nock were at 90 degrees the arrow would end up being nock high because of the thickness of the nock. Now if that line and the edge of your square represents the bottom of your arrow then you will probably be ok.

I agree with Tfox, if you moved that nock to the top or removed it all together it would give you a better nock position if you were looking for it being square.

Again we don't know this for sure either since we don't have a clue where your arrow is when the rest is in its full up position.

Paul