I got this set of 15 Alumilite resin dyes from Rockler. They work great for silicones, epoxies, and polyurethanes, and also pair well with mica powders. I wanted a tray to keep them organized and make it easy to move them around. I printed this in transparent PC and then black ASA, but I think any filament would work fine.

These bottles are 32mm in diameter and have the color name printed about 24 mm high, so that's how I picked the outer wall height. The interior walls are slightly lower just for aesthetics since these bottles are tall enough to grab either way. The exterior walls are 2.4mm to be six 0.4mm shells, and the interior walls are 1.6mm to be four shells. Everything is parametric, so feel free to modify the Fusion variables however you like.