I designed those Paint Bottle Holders to be as filament friendly as possible by only have a 1mm wall around the bottles. I also include the parameterised Fusion 360 file so you can create fitting holders for your own bottle sizes.

The 26mm holder holds Vallejo bottles a bit loosely, but since I use mostly Citadel Colors which I refilled to bottle droppers from amazon I had to go a bit bigger.

https://kurtgierke.com/blog/2024-05-12-paint-bottle-storage-with-gridfinity