I had a 25 inch rear tire on the 350 this summer like yours. The bike was unstoppable.
Every time I thought that I had created a long term extraction project, the BW just powered out of whatever hole I found myself in.
High speed through the mud is an entirely different kettle of fish. It's a little bit like a game of roulette, guessing what direction the bike is going to go.
And don't even get me started about river crossings, with all of the flotation and no spokes to let the current through...