This spool holder includes a side and top display for models and filament information.  Use tape to secure the printed panels to the spool holder, that way it is not parament. If you put something like a benchy on the top you will need to take it off when taking the filament on or off. 

You could glue anything to the top panel for a color reference. You could put benchies, temp towers, calibration cubes/cats/dogs, or just anything that will fit on the top panel. The screw holes are designed to be used with m3 x 10mm screws.

I printed this without supports at a .28 mm layer height. Print with the screw hole touching the build plate. Using 10% infill with pla is strong enough to hold a kg spool.