Personally, I completed them as part of a large team charming the earth library section during Rapid Respawn. I was in the same situation as you: I had finished the Cursed Books already, but I kept charming and even joining another team the next day purely to complete the Ink Blobs most efficiently. Consider using a Bestiary Betterment potion to speed things up. You should be able to make some progress on the Biting Books as well by fire bombing the room to the east. If multiple people in your team want to do this, to avoid fire bombing over each other's bombs, I recommend for three people to use a single fire field on any of the three tiles here:
This works since the books are guaranteed to walk over them as they exit the room.
Another way to complete Ink Blobs might be to set up a team hunt in library. It doesn't matter which section, as you point out, since there are Ink Blobs in all of them.