Bo,
I approach grading systems with this simple concept: how can I best measure learning? So, is this accomplished by a lot of daily quizzes? Or perhaps the homework plays a bigger role than usual. Or maybe the project serves to demonstrate comprehensive learning. In programs where there is an external, post graduation credentialing or licensing exam, exams my carry more weight. In general, weight of the different components should be based on how we can measure learning, keeping in mind that there are many ways to achieve that, and we want to be as accurate as possible.
Barry Westling