For my IKEA KALLAX drawer, I had to use the 275x300 size grid an boxes; my collegue have the other drawer, which has an other size; he had to use the version with 270x300.
Please print first 4 times the grid to see, if it is working for the boxes, which takes more time to print ;-)
Or, you can measure it.
The boxes has a lid, which can be label with a P-Touch.
Hope, this design will help you to organize small stuff with your IKEA KALLAX Drawer.