What Screws? - New X-Pole Permanent Mount

Wondering if anyone has experience with the new (square) Xpole permanent mounts and what (diameter) screws you used? Waiting for the pole to arrive (so don't actually have the mount in hand yet) and headed to the hardware store hoping to pick up everything I need ahead of time however I can't seem to find the recommended diameter of the required screws... thank you in advance!