I acquired a set of GBC Gators for my V-Force (same size as the stockers) and am very happy with their trail performance (including mud and coal piles)...

 

I've got 22x11 Dirt Devils on the back of my V.... they do awesome in the mud and soupy trails. I also put some 22x8 Mudlites on the front mainly because they clean so well.... and the Holeshot XCs would just cake with mud where I rode, making it impossible to steer. Overally very happy with 'mud tires' on the V-Force! GO for it!

Here's a picture of it... http://www.lickensworld.com/pictures/700Mudlite.jpg