One of the most important things I've learned about customizing, adding-in, or modifying curriculum for my kids is that I can't write anything down in a schedule. I will be much happier if I just go with the flow. This year, I'm using BKSK 5 with a 13b, 10g, 8g, and 6b and modifying for all by flying by the seat of my pants ;) That is why I will use a title like 1-ish...
The biggest complaint I've read in the forums and on Facebook is that the World Book Encyclopedia is boring and difficult for a 5th grader to read. Sonlight and Bookshark released their own version of a spine called Eastern Hemisphere to replace the World Book. This book really isn't any more 5th-grader friendly. It's certainly full of important information and I like reading it for my own knowledge, but reading it out loud to a bunch of kids? Bleh.
Now, my 13b can and should be able to read the World Book Encyclopedia/Eastern Hemisphere book and fill out the Notebooking pages. He does this in his own study area where he won't be distracted by the younger kids. I am having him use BKSK 5 as a Geography course only. His history this year is BKSK 8.
But this is my big secret for my middle three: I use the scheduled Read Aloud to hook their interest. After a few days of getting into the story, my students are ready for more information about the country that the story takes place in. Bait and switch, baby. Where the Mountain Meets the Moon is a delightful story that all my kids are enjoying.
Today, before everyone was all settled and ready for some story time, I casually introduced some interesting age-appropriate information about China from the Eastern Hemisphere book. After I read the chapters I could read from Where the Mountain Meets the Moon (I can't follow the schedule, I have to follow what I can do with seven kids in the house), I quizzed them on the facts of China and then....
....we made rice (and only rice) for lunch. Just like Minli!