The author remixed this model.
The space between each square of the original trays is only .4mm thick, so I added an extra .6mm to the inside bottom surface to a bit of strength. I also added a 3x1 and a 4x1 size to fit longer items. Finally, I made 4x4 and 4x2 grids to fit larger drawers and to take advantage of my 320mm x 320mm bed (at 99.69%).