SPC arms give you the most adjustment out of all of the companies, I believe they quote something like 3 or 3.5 degrees of additional adjustment each way. Your stock arms probably give you about a degree or so both ways.
The thing to remember with bagging a car is that camber will change as the ride height changes so when you air out you will see more camber than when you begin filling the bags. But aired out on a 6" drop will probably land you somewhere around -4 or -5 before adjustment.