wow! I have a wizard, but not the version that cuts 8 ply..
anywho, I have an old Carithers Signature mat cutter and I cut 8ply on that beast in one pass.
it cuts beautifully.
I had never thought about making a few passes for that board. interesting...
oh yeah, and i used fletcher mat cutter blades. the ".012 Super Keen". That's what it says on the box! Seriously!