He has crit IA, which is pretty much the best one a phantom can get.
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Mazz; - have you tried replacing your empress gloves with Hero's gloves? (or are you already considering that) I know you're capable of getting them, and the 20%td/40%boss damage still beats the set bonus. Give that a shot and see if it helps, or just run the math if you have a "range calculations spreadsheet".
I would skip the ark rings unless primals are cheap on your alliance (like less than 800m or something). They're not a HUGE benefit and there's supposedly 3rd tier pottable rings incoming.
Dualing up on alchemy potions will help as well. Stack resistance pots + 70+luk potion, or if you're feeling really bold, 70luk potion and 24/30att potion. (your overall DPS will probably drop from the downtime though).
Finding a decent AB hat to swap on and off when rebuffing will be a good boost. IIRC it's 20 attack. May as well get decent CO if you see it cheap, it'll improve your carte dmg and Dark Harmony.