I forgot to mention, 3mm depth. 1mm/pass, 15mm/s feed rate. 1/8″ bit. 45% stepover.
The words took about 1.5 hours. Each warning sign was about 5 minutes.
I used Estlcam to make the words, and I found an image on the tubes, imported to inkscape, converted it to an svg, and then used estlcam.
These settings seemed really conservative. I was using the HF speed control, and I had it at the bottom. I think I could probably go at least 3x faster. Great settings for a first project though.