Available nighttime reservations for the Munich Oktoberfest are rare. Weinzelt (Wein Tent) now offers some additional tables for Oktoberfest 2017.
Weekday evening reservations are pretty rarely seen freely available, as they are mostly occupied by companies. The Weinzelt now offers three additional evenings: the first two Mondays and the first Tuesday, from 8:30 pm to 12:30 am. However, the reservation form is only available on the German-speaking website. The English-speaking one wants you to send an email.