Using this guide, our team rocked the trial in less than 45 minutes. We went point-to-point, taking out the Rikti, then the Krakens, the tentacles, and finally, the big Head.
Of course, our team consisted of 2 lvl 50s, a 47, a 43 (me), and a 42. The 39 & two 38s were SK'd to the higher lvls once they got the weapons, so killing the mobs went very quickly. We weren't shooting for XP, although we got a fair amount of that, but to complete the trial, and earn the badges.
I wonder if they've changed something, but no Rikti spawned while we were zapping the Hydra head. I kept watching its health bar go down, all the while warning my team to expect Rikti to materialize right on top of them, yet, the Rikti never appeared. Not that I'm complaining, mind you, since things went even faster, I'm just wondering if they always appear, or the trial has changed since this was originally posted.
All-in-all, a most excellent source of information.