If we do have a night always, I think twilight of 12h would be fine? But sounds good either way
there's a certain role that uses the twilight phase, twilight can be shorterened only if that role mails me before those 24 hours (and when that role dies, twilight can become void). but a lot of people have night actions and they are allowed to send me their actions through pm during twilight to make the night go faster, i can instead make the minimum night lenght 12 hours but keep the maximum still at 48.
night actions send during twilight are not final and may at any time be changed during the night that follows, in case something happens during twilight that may make you change your mind about your night action.