Grats on the kill!
My guild uses an easy strategy on the 2nd gauntlet phase when we are burning the boss down to the 10% transition.
There is 'Wind Channels' on the side of the gauntlet which if stepped in give about 200% movement increase to the other end with only minor dmg.
At 11% when the boss is about to fly to the other end we leave just a tank and healer and have all the other raid members use the wind channels and move to the other end of the room and wait for the boss to fly over. So by the time the tanks get there, hes dead
Here is an example from our 1st hc kill, which we left both tanks and just moved the whole raid over and left them to burn, well our sucky dps tankadin at least