Accuracy by encounter?

So we all know the approximate "caps" (after which any more accuracy is wasted) for Twintania, if I'm not mistakened:

All 4 Melee: 472?
Summoner: 450 base, for the pet, otherwise 432? for the SMN himself
BLM: 432?
Healers: N/A, same as BLM most likely but not what they should be getting of course
BRD: I have no clue

Sooo I was wondering, other than Twintania, how much can you lower your accuracy without missing a whole lot against the Extremes, other coil bosses, Hard modes, Pharos, etc?

Not sure if I am right about this or not, but since the EM's are all lvl 50 shouldn't that be the same ACC requirement for all lvl 50's? I'm relatively sure thats how the system was made. I'm sure T4 and Twintania still hold the highest ACC requirement across the game, excluding world boss Odin (lvl 59, hah. stack that ACC)

I had my atk miss once (PLD) on Turn 2 and my acc was 471. Pretty sure for malee Turn 5 it about 481 ish