You can see what time it is currently, say 11:22 PM EST and then find the value in the Time Offset that would make the newday in 48m (48 minutes). Then, you should be all set up.
The server that I am currently on is in Germany, so mine is set to an offset of: Next new day 06:00:00 am (00h 36m 40s), which is +6 hours from where I am, so a newday occurs at 12:00 AM EST.
If you want, you can look here:
http://kitsunecrossing.com/about.php?op=setup and click on Useful Information to find out a better take on the subject.