Never pull as PLD. Ever. You lose the most damage of all tanks by far and misalign your buff windows. If you want to MT, have the OT pull and you voke after he gains a bit of emnity and have him shirk you. Your dps combo is relatively straightforward GB RA RA GB RQ HS x5 repeat so maybe you just aren't getting enough uptime, try to stay on the boss as long as possible before going to do mechanics, ie wait until the cast bar fills before running to planeify yourself for the earthquake.