Mounting the LEDs on the back can work quite well if you have some kind of reasonably reflective surface on the back. You don’t even need a hole in the PCB, jus

Mounting the LEDs on the back can work quite well if you have some kind of reasonably reflective surface on the back. You don’t even need a hole in the PCB, just a gap in all of the copper layers. I used this approach in my light meter project: https://github.com/addrummond/mlm https://github.com/addrummond/mlm In this case the reflector is just plastic painted with gloss white. Also, awesome project!