I'm doing the 24 hours right now using the 787B, and I get 6-7 laps on RH. I can go about 1-2 laps longer than AI as well, car completely stock and after three hours, I'm 3 minutes ahead.
Setting camber and toe to 0 wouldn't be the best way to go about it, though. The lack of camber will reduce lateral grip and cause the car both to understeer and to wear through the tire and toe should be utilized to best manipulate the car's behavior, whether it is set in or out.