RE: How high above square?
If the front of the arrow passes the riser at the same height as the berger button hole, then you should have enough clearance. Tiller will greatly affect where the nock is in relation to the string. If your best tune comes with the nock a long way above perpendicular, then adjusting tiller will bring it down as far as you like. It can take a lot of experimenting with tiller to find out from what position your best nock travel comes from, which will give you your best groups.