These standoff covers are interesting. I’ll be sure to throw them on my next KBDfans order.
In the spring, I poured a custom silicone case dampener for my aluminum GK64x and it improved the sound and feel of the board dramatically. I had been looking at various foam options but this silicone pour was cheaper ($13 in material) and seemed to be the route that a lot of higher end customs were using (RAMA and ai03 in particular). It also seemed like it could be an easier option than foam because of all the nooks in the GK64x case I had. I followed this YouTube tutorial which was incredibly helpful.
The most important thing is to make sure that the board is 100% level (with how the PCB fits in the case) because you’ll run into a ton of issues otherwise. I used painters tape to cover any holes in the case and then poured the silicone almost up to the top of the case mounting points. Like foam, you want the silicone dampener to compress a bit when you install your PCB. Here’s my case right after I poured and the silicone was still liquid:
I let it cure about 18 hours just to be safe. After that, I started with a little tab of painters tape by the USB port and just very, very slowly peeled the (now solid) silicone out of the case. This is what it looks like once it’s cured (note that the silicone is flipped upside down in the photo):
I can’t recommend this highly enough.