I was going to ration HP, as well, but having just finished the last book myself, I've changed my mind and intend to discuss intensively as my DC go, instead. DS8 is in book 4 with no discomfort so far (& he's the sensitive one).

My DC love D'Aulaire's and it makes for a nice springboard into non-fiction about ancient Greece. Strewing the house with books on themes, like the ocean and space, has worked on my fiction fan, while historical fiction has had the same effect on my non-fiction fan.