Every congregation has its own approach to structuring religious education. You can implement Riddle and Mystery with any model your congregation uses. For example, you might need to offer it to an age group wider than sixth graders in order to assure a group of reasonable size. If that is the case, seventh and eighth graders might benefit more from this program than younger children.
As a leader, you will choose the combination of activities for each session. You know best how to shape the program to fit your congregation's religious education model, the culture of your congregation, the youth in the group and the time and space allocated for each session.
You may not have much choice of a space for Riddle and Mystery. If you do, choose a room large enough for youth to move actively without worrying about damaging fancy congregational furniture. Ideally, the space will allow you to leave the WCUU/KCUU studio in place from session to session.