Hi Dara,
Following up on your ways to earn an A or F in your class idea I would recommend the following. Take the same information that you are currently giving out and turn it into a contract for an A in the course. I do this with some of my classes. I list the ways one can earn an A in my class so the students get to see all of the positive aspects of the grading format. Along with that I also list how one can have the A slowly taken away such as with absences, late assignments, etc. I list the penalties for each. This way they are informed about consequences but I do it with the idea that I want them to all earn A's in the class if they will put forth the effort.
Gary