The more I read and think about this the more I think Hilton really needs to issue a certain number of Suite upgrade certificates to Diamonds (using some sort of calculations/ratio) and enable them to book the upgrades themselves when its most meaningful to them in addition to the current Roulette. At the very least set a window for them to go online and check-in and claim an available suite upgrade during a certain window prior to the official check-in time (such as 24/36 hours in advance) and anything not claimed by that time can go the current hodge podge method.