I am trying to bring the smallest pack/weight I can. How small a water bottle can I get away with to last between refills? Or, put another way, what's the longest distance between water? I'm sure that my Camelback would be plenty, but who wants to carry 100 ounces of water if you only need 32? I'd prefer to carry my one liter steel bottle if it is sufficient. (I realize that i can fill the Camelback halfway. But my smallest pack doesn't have a sleeve for it, and I like not using the plastic if I can. Using it would add 2 lbs just for the larger pack). Thanks.