I was under impression that receiving the weird tome sets Literacy to 100 (I'm almost sure that I read it in GB, but can't find the info) not chatting with the librarian. I haven't tried myself, but it kinda bugs me.
Speaking about the new potion of literacy: I've recently received it with Literacy slightly above 50 and drank it to receive an increase to 65 or so. This looks really low, is this the normal average increase?Scratch that, found the answer.