Persinallly, for me around about 8pmish is a good time for an event, as i usually have tea for bewteen 6-7pm and therefore it allows me to do a few other things in the evening, but then again it means that americans would be doing the event around 4pm ish, which clashes with their evening meal.
it really is a hard situation to get around, because if you do it at lie 1pm gmt, unless its on a weekend, people will be at work/school, but then americans will be at like 9am/10am which means by the time you are half way into an event.. they need lunch. and its the same vica versa for americans, because especaially if its around 10pm, if youre like me and still in high school and if i stay up past twelve ish, my sleeping pattern starts to slightly mess up, so by the time im half way through an evevnt, i have to come off.
it is very tricky and too be honest i donb't really know how to do it unless you make the events an hour earlier or something like that, but then that will proberally interfere with peoples meals.