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Do you mean you can play midnight to 12:00 Saturday/11:00 Sunday? 12pm usually means midday but I doubt you're trying to say that you're free to play for 23 hours on Sunday. If you mean midday to midnight Saturday, something like 20:00 GMT+0 Saturday would be nice for me, if you mean you can play midnight to midday then I guess 11:00 GMT+0 Saturday will have to work.