My Mouser shipment arrived before I finished the enclosure, so I decided to populate the board. I've finished drilling the enclosure though.

The bit of JB Weld is filling in the old center punch dent for the LED from before I changed my plan.
The output jack will be directly below the donut hole, but I believe I still have enough space to work with. I'm currently planning to put a small piece of painted aluminum flashing in there. I think there will be a large enough gap to hit the flashing with some light from inside the enclosure. If that doesn't work, then I'll just have to think of something else.
