Should I be commenting and assigning a score to ALL proposals, adding a comment "none?". In many cases I don't have an informed view, or others have said it all already. And doing this will increase the torrent of emails, under which I am already floundering!
I would only recommend reviewing proposals that you're interested in reviewing. You might end up ranking a proposal that another mentor has asked a student to clarify or improve. That might give it a lower score than it ultimately deserves. Think of it as a very slow race condition. You should be able to turn off email updates on your Profile page. It took me a while to figure that out too.
I'm not convinced that a scoring system will prove necessary at all?
I'm not either :) It changes from year to year...