Print one "spoolMain", two "spoolCaps" and 3 hooks. This uses the same hooks as the thing linked in the description, stl posted here for convenience. You'll also need 3 16mm (I think) M3 screws, 3 nylon lock nuts, and I got my rubber band for free at the grocery store! (with a purchase of carrots)
Caps are a tight fit, and if you get "elephant's foot" on your "spoolMain" print, you'll be doing some clean up before you get the cap in there.