CGMiner's unable to set voltage on my dual 7950s as well, I read something about why somewhere but I can't recall atm, so I do that with Afterburner. As for the threads, I never used that config editor, I just put my variables in the profile editor, which is -g 2 for my cards but I don't have to specify it as that's default. Not sure what to say here, try it the typing way, or even not specifying it at all and see what goes? In my case, I just copied what I had in my .bat file altogether into CGWatcher's profile manager.