Inspired by this design from Instructables - it failed when I printed it, so I decided to design my own from scratch.

Recommended print settings:

• Material: PLA or PETG

• Layer Height: 0.2 mm or less

• Infill % : 30+

• Supports:  No

• Print Orientation: Default as modeled 

• Brim: No

No supports. The openings are for the MakerBot spool holder to clip onto, then a normal spool will hang on the post. This does require that the "drawer" be left open on the Replicator+.

Test print for retention: