Did the 63 quest at 63, with full i270 (remember that you can augment Shire gear for that 10 ilvl boost). Did lose once. Tried again, putting more effort in, and it wasn't too bad. I'd say the most important part is definitely just waiting after each fight until all your cooldowns are up. That point alone is why I would say the quests aren't as bad as they might seem. SMN has so many oGCDs to throw, it's not a huge problem. Just be sure you're throwing everything. Using Ifrit the whole time, mind. Titan not worth the trouble.

Admittedly, I did also have chocobo out, largely due to threads like this suggesting it would be a struggle without. Maybe that made a difference, maybe not. Did also throw a potion on the hotbar, figuring I never use them otherwise, may as well help me here.