-I used SAB/RAV/RAV to stagger the boss while throwing up deprotect, deshell and imperil, so I assume it shouldn't be too difficult to stagger the boss with two ravs.
-I don't think you would need a Sentinel unless you're just switching to SEN/SEN to reduce damage, most(maybe even all of them?) of its attacks are area of effect
-Target time for me was 11 minutes, I did it in 4. It took me two attempts to defeat the boss, first try I staggered it once but didn't kill it, then didn't manage to get it staggered again... The boss has a lot of wound attacks it will use if it isn't dead after the first stagger, and my party just couldn't pull through once it had 50% of its HP as max. So on my second try I did everything in my power to kill the boss in ONE stagger. (Stagger, Ultima Arrow, Multi-cast, once at 999% paradigm shift to Cerberus, use Kweh, change leader, Meteor Javelin, and that did it.)
hope that was useful info for you
EDIT: why the hell does the AI prioritize Poison after Deprotect? Damn that annoys me!