You may as well waste any limestone that has dirt mixed in it. If that was my driveway with the problems you have, I would it excavate it deep enough to make room for 6 inches of three inch stone, then top it off with CA7 limestone. I have done that and have had excellent results ----> A driveway that drains and will not settle. I never put CA6 or any gravel with fines in it for a finish grade because it compacts too tightly and will develop puddles like you are having problems with. CA6 is terrible to have in front of a building because the fines sticks to tires and will always make a floor dirty. Especially when the driveway is wet.