Changing the absolute tolerance settings applies forward from that point. It doesn't go back and change geometry, surfaces etc that have already been made. Not sure where your hexagons are coming from. A circle at low tolerance is still a circle. If it was an extracted edge of a surface made at low tolerance perhaps. Maybe your cam is using the Rhino tolerance for what it does so maybe just changing that will help. Be suspicous of trims; check intersections with the analyze>curve>geometric continuity tool. Recreate any really critical surfaces.