Um, depends on a couple of things. If you have Innocence and which way you go with armor.
I dance with crocs on a regular basis with around sixties in armor/parry/evasion ... however that armor is heavy plate and I have Innocence.
If you're purely dependant on evasion/parry, and can't shoo 'em off with Innocence, I'd say at least up toward a hundred. I'd get badly smacked around by 'em before I got Innocence and killed once. (Ok, so I wasn't paying anywhere near enough attention to that third wandering in and was messing with a blood worm at the time.)
Crocs are generally rated around a hundred or so, maybe a little higher, but as we all know, its different as an empath.
Dio