I finally came across some filaments that were so rough that they weren't pulled efficiently through the filament sensor and the PTFE tube to the extruder from the back (Fluorescent PLA and wood filaments). Re-purposed some designs to create this stand to feed the filament directly from the top. You can screw in the original filament holder or use the one that is shown in the pictures: www.thingiverse.com/thing:2431785. Required screws: 2x 20mm M3 2-6x 15mm M4 (unless you glue the stand and extension together).