The original model looked like exactly what I needed – a RPi 5 case that I could attach to a mount for a HSW. Except the posts between the top and the bottom were printed separately, which I found confusing. I didn't need the bolts to go all the way through, just up through the HSW mount, the bottom, and then enough into the top of the case to hold everything in place.

What you see in the photos is the bottom as the original designed intended, but the top has been modified to include the posts. Some 12mm bolts up through the HSW mount were enough to tightly grab the lid and hold it in place.