Also, you could look in to the mod for reducing internal resistance in the tailcap spring and switch. Just search for "maglite resistance" or something and you'll probably find a thread with the whole procedure. It's pretty involved, though, so you might want to do that at a later date. In lieu of that, you might apply a deoxit product to all contact points on batteries, spring and so on to reduce resistance. Every little bit helps the brightness!
My fault, I've tried to navigate without being redundant, someone recommended the ROP to me and somehow my (apparently bad) searching didnt catch that useful sticky.