I'm going to take a course and do SARTECH II, and I got a list of the required gear. Since I already have five or six headlamps and flashlights, of course I started thinking about getting more. None of the lamps/lights I have are strong, nor do they project very far. I picked them for longevity -- except for the lights I use for shooting. As I began looking at high lumen headlamps (I am guessing headlamps are probably best), I realize amidst the myriad choices, I'm not sure what features I should look for. Please advise, oh sages of ETS!

PS. We're advised to have backup lights, backup batteries, bulbs, etc. So I'm thinking of things like deciding what kind of battery to use for all lights (CR123 or AA), whether to have all headlamps or a mix, etc.