Hi George,
Server Time Zone and Server GMT Offset are the actual offsets for the server time. Note that the offset for a given time zone may be different during different times of year, hence the difference between GTB Standard Time with a GMT offset of 2 and GTB Daylight Time with a GMT Offset of 3. Apparently at this time of year it is GTB Daylight.
Similar, where I live its Eastern Daylight Time now so we are -4 GMT, but next month I think we fall back an hour to Eastern Standard Time which is -5 GMT.
Preferred GMT Offset can be set in user.config with
<add key="PreferredGreenwichMeantimeOffset" value="-5.00" />
so if your server local time is the same as your preferred time zone then set it to 3 for now and change it to 2 when Daylight savings time is over.
Like I said in a different thread, now 3.5 .NET has a TimeZoneInfo class that we will use in the future to make it so we don't have to adjust it manually because this class knows how to adjust it automatically.
Best,
Joe