Doug, I have always use Tomahawk 9x9x24" which I think is a model 108 or something like that.
But have also caught them in 10x12x32 raccoon size which is okay.
They just have more room to move around and lift there tails

Chuck VD I think uses: 10x10x24"
Now bait for skunks would be a good subject some time.
JC