Assemble your paint racks any way you want. No gluing required. The clip system allows you to connect the paint racks side by side, stack them vertical, and mix your bottle styles. Change your configuration and add more racks as you grow your paint collection. Disassemble for flat storage. Here is a video of the racks in action: www.youtube.com/watch?v=qD99qx1KvIY
If you want to improve the model, I would be happy to share my Fusion 360 files for non-commercial purposes: Here are my current thoughts for possible revisions:
(1) back brace, (1) rack unit, and (4) side clips fit on a Prusa MK3S build plate (see video).
Print racks face down.
PLA prints more cleanly, but it tends to be brittle for this application. I prefer PETG, which has the flexibility that is well-suited to this application.
The author hasn't provided the model origin yet.