OK, my $.02 worth, Brian's way is similar to mind. I file under Las Vegas casinos; Nevada casinos; and non-Nevada casinos- which Indian and riverboat all go together. Thank God for that index as it got well used!
As far as variations, I made it easy, if I see no difference on the front of the card, I don't need the second card.
I would like to see all casinos (Indian,riverboat, dogtrack etc) get listed together. All in all the boat is great!!