One tank on Tortos, the other on Vampiric Cave Bat duty. Don't stand in Rockfall. Healers be ready to top the raid after Quake Stomp. Kill priority is bats, Whirl Turtles, then boss. Be sure to kick one of the turtles into Tortos to interrupt his Furious Stone Breath. Although you can mostly survive the breath on Raid Finder difficulty, make your healer's life easier by interrupting.
Note: You will have to kill the three Eternal Guardians around the cave and ring their bells to spawn the boss.
Tank the two active heads facing away from the center, and don't tank the same head twice in a row to avoid debuffs stacking too high. The raid should stack in the center during Rampage for AoE heals. Kite the beam out of the raid if you're targeted with Torrent of Ice. Run out of the raid for a Cinders dispel. Run away from the Acid Rain. Kill order of the heads in this difficulty isn't too important, just rotate -- green, red, blue will work fine.
See Ji-Kun's quick strategy after the break!