Recently bought some 3kg spools of filament. Therefore i needed a larger spool holder than what i had, so i made this.
It snaps right on, the left side of the P1P. The 2 pictures from tinkercad shows the 2 steps (Screw holes are built in, but it sits on really well without).

It uses the original bowden tuber coupler, which gets mounted in the 2 holes at the top of the printer. It uses the original screws, that can just thread into the plastic.

Requires 4x M3x10 Screws to secure the spool holder to the mount. Other than that everything works by just pushing things together.
 

Theres 2 different mounts, i have yet to test the honeycomb design. But made it to save some filament.