Print with your default print settings (I recommend 0.2 Layer height). Depending on your printes bridging ability, I would recommend to support the USB cutout.
For the RGB diffusor, I printed mine in transparent PETG with 3 layers of white on top where the LEDs sit. Without the white it was not as nicely distributed and the LEDs much more noticable.
For PCB and BOM see my GitHub: https://github.com/exen904/ISO13715-PCB
The author marked this model as their own original creation.