The pot-size is 4,5 mm and 6 mm wide. I made one stand for each.
In the bottom of the pots i threeded a selfwatering cloth, cut in to strips. All stands are all put into one big box. This way the plants will manage to get the water they need.
The actuall holes in this stands are:
Plantstand 4,5x4,5:42,50 mm
Plantstand 6x6: 58 mm
The box is now located under my roof windows in the attic and the plants are doing great.