For FDM printers, it's recommended to print the case with the phone slide-in cutout to the bottom of the buildplate and cura "experimental tree support" enabled.

PETG with 20% fill-in is robust enough - be careful with the fan grille on the back when removing support.

If the printer is calibrated, the case can be printed without rescaling. The phone cutout has a tolerance of around 1mm and adding a layer of PET fleece tape to the edges of the phone is recommended to tightly stay in the case.

The fan is a 60mmx7mm PC fan - 9mm might work as well but will be less effective.

The mounts are attached with 2x 35mm M3 screws. Self-tapping 30x3.5mm screws should work as well if there is no intention to swap the mounts.