Based on these amazing designs:

https://www.printables.com/es/model/409347-spool-weight-holder-for-bambulab-ams

https://www.printables.com/es/model/422882-spool-weight-for-bambulab-ams-spools

I designed, from scratch in Fusion 360, this variant.

Is intended to use with used ball bearings (my sons destroy a lot on their roller hockey skates) but you can use any cylinder weight you want.

With 21 ball bearings (7x3), the total weight is around 350 grams

The size is for a Bambu Lab spool filament and 22mm ball bearings (with 1mm tolerance) but you can easily change the size on Fusion 360:

In Sketch1:

• BallBearingDiam: The ball bearing diameter (or any other cylinder you use)
• RollWidth: The body roll diameter.
  

In Extrusion2:

• RollHeight: The body height

Instructions: Put 7 ball bearings on each hole, close with the bearings lid, then use on any spool you need.

Printing instruccions:
- Use adaptative layer height
- Print well in PLA
- 3mf file is provided for Bambu Lab Studio (be aware! I use cool plate)

Edit (2023-09-03): Added tolerance to Body Lid and change turn to be more intuitive

I hope can help anybody