Percentage based shading in Yeti

Because I am the life of a party, I decided to spend my Saturday night recording a groom shading tutorial...
This video goes over the basics of "Probability shading" for fur, in this case I am using Peregrine labs Yeti.
Naturally, this video just covers one approach at a very surface level. If yyou have a different method to achieve this look please feel free to post it in the comments for us all to learn from :D