I have a couple digital multimeters and think I will definately use one because like you say one battery could be the weak link in the chain. I use my meter alot on batteries and a weak link happens more often than most people would think.

The camera recommends using Energizer Lithium batteries and I am using the Ultimate Lithiums over the Advanced Lithium due to the better extreme weather performance they cite.

I really would like to see how the Energizer rechargeables perform because I have moved to those exclusively for all the AA needs around here - which is huge. It cost me a good buck to initially get a quantity of them but no more buying AA's! I used my drill drill press and drilled holes slightly larger than the AAs at an angle into a 2 X 4 to keep them all organized. Painted red and black. Red = dead. Black = charged.

Also wondering how long a 6V lantern battery would last.