It seems like it's a good learning experience for you. If you're really having a hard time, learn the legit fight in normal mode. The two fits are identical except the Templar does more damage and has me health. Try out different positioning. Decide if you want people spread out to deal with oracles, or if you want to camp it out in one area and get cleansed everytime you get marked. The fight is much simpler than atheon and besides the detain thingies, there's a lot less randomness too.