How about every two months to start with and see if that works? I’m sympathetic to John’s suggestion of quarterly but if part of the aim is to exercise one’s writing muscles with different stories or styles then frequency seems relevant. So maybe see how we get on and go to quarterly if that’s necessary?
If we did open votes would voters give a critique of their chosen story as a way of providing some feedback? Just a thought. I don’t know if it’s practical. One Denizen’s critique, posted first, might influence later voters. Though I know we’re all rugged individuals 🙂 Dunno, I’m happy to go with the flow.