Maddog, I put a little more pressure on the point with antler than with stone, copper, or steel. Antler is a little "spongy" and requires a bit more pressure to release a flake. The pressure is about the same as the pressure needed to break the tip of a sharpened pencil. You've got to be VERY careful with the tip. It took a couple months for me to learn to sharpen the tips without snapping them off.
In one video, I show a fire-hardened antler pressure flaker. Fire hardening eliminates the "spongyness" but makes it weaker and more brittle. I don't like using fire-hardened antler very much. It's useful only for tips, IMO.
You're welcome Jonathan!