I also needed to make some drawers to hold stamps which will be accessed from the side of the book. I usually would use Altoid tins for this, but they are too deep and were taking up 1/3 of the thickness of the book. Cereal boxes folded into flat boxes and covered with paper work fine.

They go in the side of the book. See the gap where one will slide in on the book at the bottom of the stack?

The next step was to start cutting the niches for where the stamps will go. I'm learning a lot this time about the value of sharp blades. A few times, the dull blade was pulling on the paper and causing it to rip rather than a nice clean cut. 

This is also my first time using gel glue. I'm pretty happy with it. 

So the really tricky part about this book is that it will have many thin niches, rather than one big one attached to the back of the book. Some will need to be accessed from both sides (this will make more sense later.) I've one ever done a book with one main niche and then another one half-way though, and the book nearly came apart. This may not work, it's an experiment for sure. 

I'm cutting all of the niches at the start, since it's a mess to cut one after a further page has contents, is collaged, etc. The varying sizes are based on the sizes of the stamps that will go into that niche.