My guild killed it 2 days ago. We used 2 tanks and 4 healers. Our strat was we push Fel phase without hero before 3rd fel nova. Honestly the second one is pretty easy to manage since you only get 8 marks instead of 16 from Grand Conjunction. We hero p3 to burn first add and then ignore the second one. We tried heroing p2 but it just wasn't worth it. Our dps was more than enough anyway so we decided it's better to save it for p3.
Here is the logs from our kill:
https://www.warcraftlogs.com/reports...pe=damage-done