Tank Busters Mitigation

[Reynhart]

Imo warrior was/is the best for that fight because they can have inner beast up for every tank buster (usually)

So, your answer to "How do I do it as a PLD" is : Play WAR ?

In all seriousness, Iceboy, don't forget that PLD can use Stoneskin itself with its otherwise useless MP. If you have 9900 HP max, Stoneskin absorbs 990 damage. On a 6k hits, it equals a 16% mitigation.
Not too bad if your pair it each time with another CD. Your rotation will also depends on your current HP. If you're full, Stoneskin can basically be enough, especially if a SCH or AST shields you, and it saves your bigger CD for harder parts of the fight.

Also, if you have only ranged DPS, you can even move Odin to "delay" the attack, but I wouldn't recommend this for the basic method.