For most mats on our Wizard 8000, I use a big 40x60 backing mat that stays on all the
time, then a 32x40 one over that which sits behind whatever mat I'm cutting. For 8 ply
mats, I remove that smaller backing mat, so only the big one remains. If you only have
one piece, you can also practice by cutting a tiny window (i.e. 2x2") from where the
fallout will be. Just make sure you account for the inch and a half extra it adds if you
cut the outside. 8 ply's take a 20 depth on ours, so it can vary between machines.