1800 UTC is 4:00am for me, so RIP us Australians.a) There's no reason it couldn't be two time a week instead of one - say, 01:00 UTC (which is evening US time, 6-9pm) and 18:00 UTC the next day or something (which would still be accessible to some US folks, morning/early afternoon).
b) Even then, 1800 UTC Saturday or Sunday might be doable - cover all of europe and US, would probably miss East Asia but we have much fewer people from there. We'd have more overlap with regular leagues and other stuff, though, so it might be better to have it be in the evening on a weekday. Even 01:00 UTC might be doable for _some_ Europeans, right?
0100 UTC is more doable for me, though — that’s 11:00am AEST so it’d have to be on a Saturday/Sunday morning to get around school. I know there aren’t many Australians, though, so you are in no way obliged to accomodate us.