Just make the game be 30 hours. It will be close enough to 24 hour rate that it will not be noticeable (especially if you do not have people submitted at the eleventh hour every turn...), and will give leeway for people in very different time zones with limited playing times... I know I have been in games where I was the Last to submit a turn simply because the turn processed in the middle of the night and everyone else in the game was in Europe.
