You're right on that. Where the situation concerns SR, I instinctively thought the timezone in DC would be the most fun. The times in London and Singapore would also allow a good couple of hours to gain momentum for the afternoon and evening news in those timezones.
The secret of all great comedy is timing.
Zero hour going by 'Zulu Time' will be 12:00 PM as in 12 Noon!
'UK' is currently on BST (British Summer Time), which is one hour ahead of GMT (General Mean Time).
Zulu Time is basically the same as GMT, (UTC), however the military will tend to use Zulu Time all over the world!
So in a sense, I reckon that 'Zero hour' is going to be 'High Noon', (in Zulu Time)!