Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:6140521.
This filament guide uses a tube to constrain the angle of the filament as well as its position. This solves an important problem with the spool rotator that isn't solved by regular “ring” type filament guides.
When the print head moves across the print bed the filament changes angle with respect to an overhead spool. A ring-type filament guide acts like a fulcrum and turns the filament into a lever that applies pressure to the overhead spool. That is enough to interfere with the spool rotator.
You can use one or more of the 40mm or 80mm arm extensions to position the tube wherever you need. And you can print one or more of the tube extensions to make a taller tube. I found that one extension tube was perfect for my arrangement.
Assemble it with 4mm hardware.
Spool Rotator: https://www.thingiverse.com/thing:6114566