[Organizers] Length of Dance

Hi All, I'm in the process of organizing a new dance series (old style Community Contra with a variety of dance forms). It will be on a week-day evening. I'm wondering how long others run their regular dances, not including beginner sessions or potlucks or such. And typically how long is your mid-break? Thanks! Sue Robishaw, U.P. of Michigan P.S. And thanks also for all the sharing that has gone on in the past on Shared Weight. I have lots of good notes and ideas from past posts (from the Callers list).