Let us think to small PCBs and you solder the edges. Metallized edges are not standard. 6 PCB to manufacture is not cheap. How to test before assembly. How to hold pieces during assembly?
We solved these problem with a simple PCB design using V-grove scoring (like chocolate) and plated through holes just in the middle of scoring. So the contact is established before breaking down, and when positioned at 90 degrees, the half metalized holes are ready for a drop of solder.
A tricky path on the PCB allows to test the LEDs and the initial software.
The RGB MiniCube is available now on Tindie.
More on https://www.didel.com/MiniCube.pdf