The great, modular Filler system by HugoG deserves a lot of credit. 

This V3 design considered the following to improve on HugoG's design:

• Easier to print 
• Minimal material use
• Minimal use of space
• Strong
• Easy to install
• Backwards compatible with the Filler system

To improve on HugoG's design, I designed for support-less printing. Most curved surfaces have been replaced for 45 degree angled surfaces. This way there are almost no hard-to-print overhangs. For example, the filament holder can be printed standing upright, or on its side without supports. 

This system includes everything for all your wall mounting desires. 

1. Wall mounts for two 1KG spools. One UP and one DOWN
2. One spoolholder for 1KG spools
3. A self-centering roller with separate bearing pin
4. A 45 degree adapter

Furthermore:

• The UP and DOWN wall mounts can be mounted at the same height of each other saving space on your wall
• Four 1KG spools can be hung in a small space, without touching

For effective material use, I used a bit of math and design logic.

The internal space between most features is 2.5mm, which can be filled by printing with two perimeters with a 0.6mm nozzle. Two perimeters make for about 1.25mm wide, so two features together fill up the space between them of 2.5mm.

With an eye for efficiency, I conceived a holder that defies the typical straight-across design, introducing an angled approach that actively guides the spool to its optimal position. This self-centering feature means that no matter the momentum of the unspooling filament, the spool finds its way back to the center, ensuring smooth operation and eliminating the frustration of spool derailment.

I printed these with the following settings:

• 0.6mm CHT nozzle
• 0.4 layer height
• 2 perimeters 
• 23% gyroid infill
• Arachne in SuperSlicer

If you use a 0.4mm nozzle, print with 3 perimeters. (or test with 2 perimeters to see if it's strong enough) 

How to position these on your printer bed

See the last image for my suggestion. The spoolholder can also be printed standing upright. 

If you're interested, V1 and V2 of this wall mount are on Printables

Thank you to the creators who's models inspired my design

• HugoG - Filler system
• Uncoild12 - Shortened and Curved spool holder
• Kevin Kunst - 45 Degree adapter

Feedback is welcome!