Not so sure - I've run round it all recently in wet conditions and I reckon (for me) my Kanadia 3s are a better bet than my Mudclaws. Reason - it's a long race, and that shifts the comfort v grip equation strongly towards the comfort end. If your fell shoes don't hurt your feet, you're lucky, wear them. If, like me, you get blisters off the fell shoes on anything more than a few miles, wear something a bit more comfortable. The Kanadias have a pretty aggressive tread pattern anyway (noticably more so on the 3s than my previous 2s).

Jim