I mounted with screws and adhesive Velcro. Since I had the EL paper, I wanted to be able to remove it in case I needed to change/fix the el paper.
I liked the permanent look of the screws, but it does require drilling the speaker panel and the stainless. Have to be careful you don't scratch the stainless.
I used thin double sided tape cut out around the Star Trek words for the el paper then soldered longer thinner wires that go around the side of the speaker panel. There's just enough room and you can't see it.
El paper came from eBay. Be careful when they send it as they often just throw it in a satchel and it gets bent and is unusable. Get them to put it in a small box.