If you have the aca route , will you want to add the weight of the book as well?
I guess when you start putting all your things together in panniers and seeing how much it all weighs, that may be the deciding time.
Dumb question, and if you've already ordered the physical book perhaps too late, but is there a digital version of the book?
Have you thought of taking a tablet or whatever for entertainment purposes? I personally enjoyed having my small tablet on a multi month trip, nice to read and watch stuff sometimes, but again, you have to decide on whats important vs weight.