Accuracy is fine when you can afford melding. I have many crafted 220 pieces, pentamelded many of them with ACC V / IV, and I still miss just as much as before in the ex dungeons. (for some reason, Antitower is the worst of them). I'd really love to know up to how much accuracy I'm supposed to reach to avoid missing that much, when I've already spent millions on melding.
Melding lore 220 /midas with just one or two Acc materias wouldn't cut it, even close.