I can only answer in the most general terms about what camber does, since I don't know anything about drifting.

When you dial in extra negative camber on a car, what you're causing that wheel to do is put the greatest amount of rubber on the ground in adverse circumstances.

In other words, if you have negative camber on the left side of the car, when you are in a right turn, your left side wheels will straighten up off the camber and put the most amount of rubber on the ground.

Coupled with a good limited slip differential, this would allow you to power out of the turn with the maximum amount of traction possible under those circumstances.

You can play with the camber front vs rear to change how the car's behaving, and either cause it to steer out of a turn with the front wheel, or power out of the turn with the rear wheel. Whichever wheel has the more camber dominates the situation.

I've explained that very badly, I'm sure. LOL... I can only hope you get the picture from my poor description.