I tried activating for three 20-25 minute sessions and I did what you said.
It's not exactly what I expected, but by mindmapping, I realize I am comprehending more than without mindmapping at all. I plan to activate more today to get a fuller understanding of this book.
In fact, now that I know what I'm doing, I understand how the activation process works. I completely forgot that comprehension comes in layers. At the same time, I'm beginning to enjoy the process.

I'll be sure to let you know how things go after I'm done.