I designed this 8" wide shelf to sit over the top of a 1" thick cubicle wall. It's a convenient accessory, especially when paired with the two hooks I designed for these walls, too.
Print the shelf standing vertically to dramatically increase strength. It will break pretty easily if printed laying flat on the bed due to inter-layer stress from weight on the shelf. This shelf printed vertically is the maximum possible height on my Prusa MK3, and prints with room to spare on my Lulzbot Taz 6.
Sliced with Cura and printed on my Taz 6 this printed excellent. Sliced with Slic3r and printed on my MK3 I had to add a brim to prevent adhesion issues. If your settings are better than mine (probably they are!) you may not have adhesion issues.