Elegon is somewhat of a DPS check. You must 2 heal it, so it's also a healer throughput check. Kill 4 orbs each phase. After the 4th is dead, make sure everybody ignores the 5th wave and just uses that as free boss DPS time. It makes a big difference when you do that in both orb phases. You'll get 10 stacks this way, which is enough. If people are having trouble with the 4th, have them use 1-2 minute CDs on it. It must get down.

Be most efficient in phase 1s. You should be getting a maximum of 3 adds in the first phase 1 and 4 in the second. We lusted on the 2nd phase 1 to get him down to 50% more quickly for our first normal kill back in the day.

Have a CD rotation setup for the final burn phase. We've always done it without anybody dropping stacks. Some groups do have people drop stacks. Try both if you need to, but I recommend using a strong CD rotation and burning through it without dropping your stacks. With 10+ stacks on Elegon, it doesn't last too long.