I read on the gearbox forums that Michael Mamaril keeps moving in the Sanctuary ao he will not always be in the same spot. I'm not sure about this cuz I don't have the game yet but I thought I would point this out.
Also would you consider putting some spoiler tags to the story related achievements? Some ppl (me included) don't want to read how the missions play.
Great guide though! Can't wait to get my game and put this guide on the use