When I was capping on NIN (back in the days before DNC), I could easily stay up with 2 steelshells hitting me for over an hour at a time using a mage sub and daggers for energy steal. With waltz, I would imagine you could handle 2 of those black mandies. A better place to skill up is the Temple Uggy zoneline in Den of Rancor. You can pull black mandies ranging from DC to T, you have a zone to escape to if something goes wrong, and no one ever goes there other than to skill up parrying/shield.
Honestly, I never bought into the whole -EVA gear thing. Your goal is to get as many hits past evasion check as you can tolerate, and you can better accomplish this by pulling multiple mobs rather than wearing -EVA. If you have support you can do something like what Ruke did with mandies and phalanx II.
http://killingifrit.com/forums/index.php?s...151154&st=0All this being said, parrying is sort of a crappy skill in the first place. Capped skill will probably buy you something like a 5-7% parrying rate on hits past the evasion check. Even though I leveled it myself, I don't suggest you go out of your way to level it.