Now I watch this debate from my perch going through IDC and serving as a CA for instructors at my LDS. We do OW in two weekends: class-pool Sat, ocean Sun, pool Sat, ocean Sun. Students complete eLearning and all academic work prior to the first weekend. Instructors vary in their interpretation of mastery learning, but one constant I have noticed is that smaller classes get better instruction, period. Even two CAs can't do much to make up for the fact that there are 12 students in a class with one instructor at times. Class size translates into time in a significant way. With two, three, four students there is more than sufficient time to repeat skills in different settings, play games, etc. With 8 and up it's a struggle to get through the skills, particularly if one or more students have serious trouble. But we'll hold people back who haven't met standards, and almost all instructors will do extra work to help remediate. But remedial work outside of scheduled classes costs instructor time, which equals money. With true terrors, we have pulled folks aside and said, you will have to take private lessons to finish your course.