The regular one even looks like an AT-AT.Freaking Black Gravios is the worst beam spam I've seen in MH. Dude just doesn't stop holy crap.
But with a LBG, my strategy is pretty much the same as when I farmed him in high rank: stay to his sides or back and keep rapid-firing water shot into him so long as he's not pointed in my direction. And if he does point my way, sheathe if necessary and scurry behind him again.
Makes me miss the Uragaans from 3 Ultimate, though.