I created an start for Filament where it is easier to fill. This can be mounted on the back, and the middle will be a bit away from the case to have the entry about in the middle from to spool to have a better place to not have fumbled filament.

It is not a remix, but heavily inspired by the side holde from suit: https://www.printables.com/de/model/456234-side-filament-guide-arm-for-p1p

Print in 0.12 Layer height, with a good amount of walls and Infill to have it stable.

A PC4-M10 will fit into the end. With the funnel it is easy to load.

You can also mount this to a side holder. Message me if you need different mount holes.