Ceramics Details (Need help!)

Hi, I'm working on this project (see attachment. How much will be lost for the glazing? I know it won't be that detailed as in this render, but will it be somewhat visible? Is there a way to know how it will look before I send it in (like a trick in a 3D program, something like offset 1 mm glaze)? And do you think the structure will hold it? Should I make the top part thicker?

The glaze is around 1mm thick. So smaller holes will close (will even cost you less to close them as that will lower the surface area). The details that will be lost are the sharped edged details. So you'll still have the larger holes, but the tentacle suction cups looking parts will be smoother and less sharp.

If you follow the workflow here:
https://sites.google.com/site/3dprintfaq/workflows/hollowing -a-model
That process at one point generates both an internal (smaller) and external (larger) shell. around your object.

This process normally has you remove the (outer) shell, but that larger shell (if you set it up for 1mm) is the one you are looking for.

In other programs other than Meshlab, it's called Minkowski sum. <grin>