I loved the original design for this; however, it wasn't compatible with slightly thicker tablets because the screws protruded slightly outside the mounting holes instead of sitting flush within them. I added more spacing where you place the tablet, allowing for slightly thicker tablets to be used. Additionally, I strengthened the overall structure significantly.

This design has worked great when printed in PLA. I don't have PETG to confirm this, but it should be even stronger with that filament.

If you print them standing up vertically it needs no support. Enjoy!