Modular coral egg crate, 16mm holes, 3mm spacing, fits perfectly. Printed with 0,4mm, 0,2 layer height, 100% infill, no need for supports. Print it so the external pins are on the print surface. I do recommend PETG.

I have also added calibration print, so you can adjust your settings before printing the whole thing and make sure it fits correctly.

5mm, 8mm, 10mm height version

If you want to connect/disconnect it and can't push it with hands, beat it with screwdriver handle or rubber mallet.

Leg v3 has a hole to remove trapped air inside so it sinks easily and there are removed edges so it fits each way.

Added STEP for the mesh so you can make bigger areas.