I've designed my own filament spool shelf which is printable by a Bambu lab A1 mini with a minimum of support. The spacing between top and bottom screw is 95 mm. I added a template for easier drilling the holes which is also a helper for the correct space between wall and the screw head for the bottom sliding hole.
The wooden staff has a diameter of 25 mm, which is around 1'' inch and a length of 1000 mm.