Quite a bit harder than 320 from what I experienced. I was relatively safe defensively at 450ish, but 370 melee weapons did nothing to them. I had to sleep them to get hits. Ranged might be another story. Sorry I can't give more info. You're better off in y.gryphons in this range, imo.

~Hunter Hanryu
http://drplat.com/CombatEquipmentCompendium.xls
http://tinyurl.com/HanryuTanning

Ranged would be easier, they don't evade well but they have a ton of parry. Zealots I'd skip honestly unless you need them for boxes. Shals gen really fast but the randomness of the DP attacks makes them not so good.