If I recall the profile on the raptor is set back. I rode my raptor x 169 centered (in the holes) and had no problem with float. In my opinion the RC boards ride best from the center.
The primary adjustment from camber is using body position to keep centered instead of having the board (camber) do it for you. Everything on an RC board happens from the center as opposed to the tips on a camber stick.
Stance setback really depends on what board you're riding and in what conditions. I haven't found much advantage to moving the bindings back any more than the the built in setback when riding anything other than deep pow.