Tim wr0te that he had to weigh his summative assessments at 50% and was asking for some suggestions on how to do that in a CI format. Here is my response:
Tim I am thinking that you have a perfect opportunity here to do the summative assessments (I would assume two per year) in the form of stories. Doing that fits every requirement you describe above.
Plus, with that exam day at 50% of their grade you could have a field day reminding them maybe once a week during the school year: “Hey guys, how are you going to do on the final if what we are doing now IS the final exam format?”