Learning experience:
Care needs taken when assigning weight of projects. One time I weighted the project 10% and a student passed the course that did not pass any unit exams. After that, I weighted it 5%.
Prior to student presentations I had each member of each student submit a rubric I created with a 1-5 scale to rate each student's participation including their own. Most often each person in the group received the same grade. If I saw a pattern of low participation by a certain student, a couple points would be subtracted.