Generated some STLs with various dimensions but if you want something else then customisable FreeCAD (v1.1.1) project is included - main changeable parameters are in VarSet at the bottom of the project's list.

I use 2mm drain holes which makes the draining quite slow (about 15 seconds with the 16cm 275ml version to fully drain) - if you want to make it drain quicker increase drainHoleDia or numOfDrainHoles.

At 0.45mm extrusion width I'd say it's just strong enough to hold +-450ml of water when full. If you want to make it bigger to hold more water you probably need to go with higher line widths to make it stronger. I haven't done any experimenting in that regard though..

Print Settings:

• enable Vase Mode!

• layer height: 0.2mm

• bottom solid layers:  0*

*the model has custom inner brim - if you have problems with the print not sticking to bed then set bottom solid layers to 1 (otherwise I don't recommend this, it just makes removing from bed harder [broke my first print this way])

Extra patience required when removing the print from bed! :)