Several sizes provided as STLs. SCAD provided to allow you to create your own size. 

The image shows a gridz value of 3. The vials were empty and stayed in when I jostled it about. So I expect full vails to have a lower center of gravity and be secure as well. If you are uncomfortable with that height, just adjust the “gridz” variable to make the base taller. 

Gridfinity Rebuilt OpenSCAD Github page