I cut the dividers for the tool trays with the help of my Bridge City Tools KM-1kerfmaker. This tool has fast become one of my best friends (other than Google). The next sequence shows the trays being stacked from the bottom up, first empty and then with the tools in place. Finish with Danish oil and wax.
For the tray bottoms, some I left bare, others i covered in Skyvex-a nice thin imitation leather that bookbinders use, and some I stuck on some veneer offcuts.