Consider using Chlorine Dioxide. Much lighter and certainly as fast as gravity filtering while working unattended.

Having said that, I don't think there is a one-size-fits-all solution. Water quantity, frequency, time of year and how much you want to carry at one time all affect what the optimum choice may be.

Personal thought is that it isn't really lightweight to carry a day's worth of water if you have streams you can get water from along the way.
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Human Resources Memo: Floggings will continue until morale improves.