All kudos to dagoma for:
Now you can print his great design for your reel sizes.
Shamelessly entered into the contest for the customizer part. The design is all dagomas. The customizer in this case is a simple re-usable pattern for resizing all works where only an STL file is available. Converted first to OpenSCAD then patterned to rescale and provide a customizer UI.
After reprinting at a smaller size I realised the numbers were a little out. The original was designed for a 52mm spool. I misread that as 53mm. The original did give a nice snug fit though, so I measure the inner diameter with digital calipers on my reel and got the number 51.55. This new baseline is in the latest online customer and files so if you've downloaded this already and have a slightly less snug fit than you'd like, you should get the new version.
Video here: https://youtu.be/KyGRl6ujfBc