Here is sign I did few months ago. You can bend the tape around on itself. I’m just a get it done type of guy. Done overthink something no one will ever see.
May I suggest LED flexible light strip, you may have to cut and splice in many places (like every 3 LEDs to get it to conform to the perimeter), use super glue, as the tape that comes with it is crap. Spray a light coat of white rattle can paint on the LED strip to soften and diffuse the light. Also, play with the voltage powering the LED strip to get the intensity you’re after.