Vampire game: how would i go about creating a very customized day / night cycle, such that day is only 10% of the time and night is 90% of the time

Vampire game: how would i go about creating a very customized day / night cycle, such that day is only 10% of the time and night is 90% of the time.

I want there to be (for instance) 10 minutes of day light time and 50 minutes of night time, to give vampire players plenty to do, versus regular humans.

The idea is to instead of a 50/50 day/night cycle, to make it more night heavy, but still have daylight pop up, some time.