If you try to blow thru all the books in one pass, it's grossly unbalanced for the head and tail, and many books in-between.

I did it in three passes - which might be all in one session or might be broken into smaller sessions. First, skim them all for spelling & grammar mistakes, with a red pen. Second, read them all (but not too deeply) to identify where they make key points, with a green pen. At this point you have a really good handle on the general level of accomplishment. Third, take a blue pen and comment them and grade them.