I would get the brightest optic you can and dial it down. None of the products you mention have serious battery-life, and none of them have horrible battery life, either.I've decided on a Vortex Strike fire, but now I'm debating between the red/green or the red only.
I have heard that the "Red Only" is much brighter than the "Red/Green."
My question is do I really need that much brightness? The battery life on the green goes up significantly.