Well If you're sliding going backwards, down hill, it probably doesn't matter which way you turn. Reason being the front wheels having a heavier brake bias and unloaded due to the incline, are locked up. A locked wheel has no directional stability (or sense of direction) so sawing on the steering wheel will have little or no effect.
The goal would be to keep the wheels rolling to maintain control or at least to release the brakes as soon as the vehicle starts to slide to one side or the other. This is all just my opinion; feel free to disagree and refute my convoluted logic.