Hmm… if it's going to be a while, then I might have to rethink things.
The way they structured this Challenge really messes me up on that last batch.
First batch, Ace and Doffy I already had maxed. So I just needed to farm Cabbage since I don't have the other two.
Second batch, Teach and Luffy I already had maxed. I just needed a few books to max one Crocodile and won't be using the other any time soon so I just went for Corazon. Don't have Kuzan.
Third batch, Borsalino I had maxed and Buggy was the only other one I have.
This batch, Jinbe and Sabo are maxed. Rayleigh is the only one I need books for since I don't have the rest.
If I wind up getting the others, it won't be all that big a deal that I didn't farm them either. I have a pretty good amount of Whitebeard books from farming the Halloween Straw Hats and quite a few of the others.
The last batch though, I need Marco books (three skillups worth), Lucci books (eight skillups of those), and Sengoku (just at skill level one).