Modular dropper paint bottle holder

I have a desk with a particular shape and a monitor on a lift arm, giving me an angle on one side that makes optimizing space a bit challenging, so I designed this thing to be modular in case I needed to put some on the other side of my desk (where I have a second monitor on a lift arm).
The modular aspect of this thing makes it easier for anybody to print it and build it to a shape that could fit any type of furniture.

The diameter of the holes is 26mm, so they can fit a lot, if not all, the 17ml dropper bottles from the different manufacturers.

In this thing you can find "Bottom pieces" (B4, B3, B2) and "Top pieces" (T4, T3, T2, T1).
The bottom pieces AREN'T stackable, have feet, and are supposed ton only be printed to be on the bottom of the structure, the part in contact with the furniture.
The top pieces ARE stackable, and have 2 guides (1 lateral behind and 1 transversal under) to help align them on top of each other. (The T1 piece was only made to correct a mistake I m