Milwaukee Packout Deep Bin with Cutout for Middle Section

This deep bin has the top edge on one side cut so it can be placed in the middle section of the packout cases. The big middle bin can now be replaced with two of these.

Or use three small bins on one side, and a large open half - like the photo shown where I used a foam insert. 

Also works well with this long 3-bin with cutout: https://www.printables.com/model/849695-tall-milwaukee-packout-long-bins-with-cutout-2-and