Oh, man, this can get complicated in a hurry.
It's a tradeoff. Adding camber can definitely help the front grip in turns, but taken to an extreme it can cost a bit of contact patch area under straight-line braking. Autocross and road race setups generally differ since the tradeoff benefits are a bit different.
The bottom line, though, is to play with it to suit your driving style. Taking tire temps can help, too, to see whether you're where you need to be, but that can be tricky as well.
How much to use is going to depend on you strut/spring/swaybar setup, your driving style, and what you want to do with it. If the car needs to stay streetable you may not want as much camber as you may if it were strictly a track car.