I'm running 950 at 1.062V right now with that card. The temps have always been great for me with this card. 65C max with Furmark at the current 950 OC.
Now, obviously, your card won't be exactly like my card, so you'll have to do some trial an error to see what your card can do (I can do 1Ghz at max voltage (1.087V), but I don't really like doing that, so I keep it at 950). My card isn't all that great as far as how far I can push it, though. The temps are excellent, even at max voltage, but it won't go over 1Ghz stably no matter what I do.
Also, I don't OC the VRAM, since that's a pointless venture anyway.
And there isn't a "Power Setting/Percentage" for the 500 series cards, so you don't need to worry about that.
Edit: I use Afterburner, as well. I kinda hate the Asus OC software (both Smart Doctor and GPU Tweak).