I am new too, and going to attempt to overclock. I have mixed models (2) 480 (2) 580 and (2) 470 ::crossing fingers::. Basically the logic i am following is  updating this in to config

[type] [worker] [gpu0 value] [gpu1 value] [gpu2 value] [gpu3 value] [gpu4 value]
# cor xxxxxx 1005 1190 1190 1150 1150 1180
# mem xxxxxx 2000 2150 2150 2004 2004 2000
# pwr xxxxxx 7 7 7 7 7 7

and trying to match what is there now and going to try to tweak it. I am not sure if it is right way, but will see.