Fast pvp questions

Anybody have any idea how much those pvp resistance materials affect the duration of the sleep/stun/bind etc stuff? some kind of formula for it? Just wonder if those materials worth for the item level 90 gear.

And second question... against Bards what kind of distance do they need for the max damage minimum/max distance?

I'm pretty sure bards needs to be within 15 yalms to do max damage. I haven't found an option to put a distance-to-target thing up when you have a player/mob targeted though, is there one?