I’m not sure you understand how magnets are made. They start out completely unmagnetized, from a powder that is sintered in a die. Then they are put into a very powerful electromagnet that magnetizes them. The power of the magnetizer does not give them their ultimate strength, the composition of the magnet is what gives them their strength.

And there are not dozens of different compositions either, there are only a handful.

So if I’m comparing two rotors made from the same compound but have differing lengths and mass, they will have different strengths. But maybe that really only applies to their saturation point when the core winding is fully electrified. So maybe since the diameter of them is the same, it’s possible they could have the same force against an idle core which means the length of them will determine the drag brake effect.

But I don’t know. So I asked here thinking maybe someone else has already experimented with this.