Well, maybe I can do my own math. It looks like the server is 4 hours ahead of the U.S. Eastern Time Zone, and if the game started 7:30 am (according to the server's clock), then turns will end at 3:30 a.m. (which works out well for me).
but if everyone finishes their turn early, it'll autogenerate the next turn.. and it only forces a turn 24 hours after the Last turn. so really there's no way to nail down a deadline every day, since that deadline is subject to shift depending on how quickly everyone submitted their turns. best thing to do is check in within 24 hours of the Last time you personally submited your own turn.