Hi Jean-Luc D
About quality grades I recommend you use OUTCOMES so you'll have quantity and quality grades for each assignment ;)
I'd like to share the way I use to work with my students:
I had to take care the uploading files too . . .
So I decide to ask them to create a Blog for our subject (Blogspot, wordpress, etc) at their Blogs they have to upload all files for assignments
In our Moodle I create a Data Base activity where they type the URL of the specific assignment, comments are allowed, etc . . . DB are the most versatile activity
And joining DB and outcomes you can grade each entry with dropdown menu instead mark
Now I'm looking forward to use GoogleWave as Moodle complement too ;)
cheers