I'm doing a 24hr adventure race in kansas come late march, and I'm getting my gear together. I'm going to get a new hydration pack and use that to lug all my stuff around. Anybody have any suggestions on size and brand? Northface makes a nice "big mouth" pack, but is that too big? Anybody with any dakine experience? Their stuff is a little more MTB oriented, but will it do ok on an extended run?