I’m in the process of building up a Preonic in a Drop case this way. Tiny o-rings between the case and the standoffs (they’re soldered onto the pcb) and a length of 3.53mm thick gasket around the perimeter of the plate/pcb assembly. I tried 4mm but that way the gasket protrudes too far; 3.53mm seems to be the sweet spot (and is also readily available at the plumbing supply store nearby). Ideally, I’d want to use an o-ring gasket but I don’t think it’d be able to clear the stab housings, which jut out farther than switches. If I went full grid instead of 2x2u I’d go that route.
I’m gonna write a separate post once I get this thing up and running. Also waiting on a usb c breakout board…
3.53mm gasket fits in between the plate/pcb sandwich. Next to no compression though, would like to experiment with adding a thicker but softer gasket.
The green mat is craft foam I had lying around. still needs a cutout for usb c breakout board but you get the idea.