I dont use fiber optic or a scope..i just have a bead. But my dad has been using a tru-glo brand red dot for shotgun deer hunting. It works fine for close shots, but for moving targets aka follow up shot on a bird i dont think it would be an easy task. Hard enough to follow a darting turkey head, much less with one eye closed thru a tube.
As for the batteries. they last a while as long as u remember to turn em off when u arent using em. I would suggest carrying an extra battery in your vest just in case.
Good Luck!!