Print stood up vertically, on the longest thin flat side, with the drainage channels pointing upwards. This helps with the curves on this model, so everything comes out looking nice and smooth.
Between 0.12 - 0.2mm layer height (I'd recommend 0.16mm) and use anything from a 0.4 - 1mm nozzle. Make sure the walls are fairly thick, 3-4 should be ok with gradual infill to make sure the top comes out nice.
Pictured print was done in Geeetech Marble PLA. I have 3 of these, all in daily use, and they hold up great in the wet conditions.
The author hasn't provided the model origin yet.