The tank in one spot seems to work best for my linkshell. Just have to make sure everyone's competent. It's mostly a ranged job's fight. Try to bring a lot of BLMs, they can bring it down in no time. Make sure you are going with 8 people though. I know it says you can enter with 4, and I've seen the whole thing beaten with 4, but if you're just starting out you should probably go with 8. Getting to 50 should also help your DPS/survivability. I'd do that first.