Mike, some groups enjoy this assignment more than others, so I generally play it by ear with each group. Seems like I had about 15 pages assigned, but sometimes once they get the basic techniques down pat, they begin to do their own pages. These were high school students of various grade levels.
Some groups work strictly by the assigned pages, while some want to turn their book into more of a photo album/scrap book...but they still have to do the assigned pages.