I didn't even realize that different states had different flagstone. LOL. The guy I hired to do the replacement showed me a sample of the flagstone he was suggesting and my response was something like, "yup, that looks good. Go with it!" I'm sure you will love the end result of whatever you choose. There is a point where all this stuff gets overanalyzed to death. What it all comes down to after it's done, is you will have an awesome hole in the ground filled with clear, refreshing, chlorinated water. At that point you just pour yourself a cold one and enjoy living the good life.