Wanted something different than what was already out there so I designed my own holders. They are meant to hold a 1" dowel, anything less than .875" diameter and the spool will hit the frame. With the offset in the holders it allows for a straighter shot to the extruder. This is my first upload to Thingiverse so I'm going to post it up as a work in progress.
Printed with 3mm PLA, 1.5mm shell and 20% infill for strength. I did have to do a little filing for them the channels and ran a .201" drill thru the mounting holes.