Great question. Those are the spacers I refer to in the original post. That was an important part of making the enclosure work for this purpose as I had several wires to hide and an electrical box that required extra depth.
I went to my local hardware store and found some nylon spacers. If you search Amazon for “nylon spacer bushing” you will see what I am referring to. I also brought one of the screws that came with the enclosure with me to the hardware store so I could find longer replacements. It was a little tricky to keep the spacers on the screws as I tilted the panel up and aligned them with the holes, but you can do it.
Best of luck! Let us know how it turns out.