For finishing or to make them a little more stackable, grab a foam or mat bevel cutting tool, like https://www.amazon.com/Logan-Werks-Cutting-Straight-Bevel/dp.... There are tons of 3D-printable cutters out there as well.

Cut the same angle on the top inside and bottom outside and you can stack shallow foamcore bins in deeper drawers. Lots of other handy uses for an adjustable bevel cutter and foamcore boards.