3D Print of Nevermore Tome - Storage & Rolling Tray

I made a little mistake with mine. I thought the book "opened" oops.... Anyway, any suggestions for keeping the insert inside the cover when in say your bag? I noticed a small divot in the cover, like for a magnet, but no corresponding one in the pages. Assuming that is the magnet spot, how do i get a magnet to line up and insert into the pages? I am not pleased with the paintjob, i think ill go over it again with a different drybrush highlight.