I am not too sure if this is helpful. My experience with God’s Design Science was with the Properties of Ecosystems when we did it in a year of My Father’s World.
My children were aged 10, 8 and 6 yo. I have to say that very quickly the younger two dropped out of our readings. Even my son, an avid reader, who comprehends way beyond his age, could only manage short readings.
But, and a big but, apparently POE is NOT the best one to judge the series by.
Also, we never even knew there were other parts to go with it, it was just the book 🙂
I took it off the shelf the other day and realized that my son would manage it on his own, at 13, and actually enjoy it, because he is into nature conservation. But, I still think it is pretty advanced for middle and junior school.
If I used it now, which I could, with my younger girls, I would rather read tiny sections at a time. We use Apologia now, as I can get it in South Africa, and I can read 5pg’s at a time. They seem to love it.
Lindy