I wanted a deck box for my Magic cards with a top that fits over the bottom. So I based the measurements on a standard 60 card Magic desk. I then proceeded to expand on that to make a deck box that would fit an 80-120 card deck. The top slips over the bottom and has easy to pull indentures. The top and the bottom should slide easily together with a little tolerance between them. If you have any questions please feel free to ask.
I used a Magic The gathering card to take measurements and created a top and bottom to fit a standard 60 card deck. I then proceeded to create a taller version for bigger deck like 80-120.