Hi guys,
i was about to post a thread asking for advice on this:
we cleared normal mode often, but yesterday was our first attempt at HM, reasonably geared people (from full BM and full columni gear to a mix but nothing that should be unsuitable for HM)
we would consistently burn him to somewhere just below 10% health health, with what seemed like a decent time, certainly not approaching enrage timers that we have encountered before.
he then hunkered down and launched the salvo at us, hitting me (sawbones full BM -also tried in full columni) for 20+k and 1 shotting me as well as the rest of the raid.
we did it 10 times, swapped me out for a 2nd sage and tied the stacking/burning through that we had read about in other guides but no joy.