Yes, the magnetic paint works really well. The one I use is Rustoleum magnetic primer, it's 3 x's stronger than it used to be. I used it on the inside of my spice cupboard door. After I put the magnetic paint on the inside of the door, I let it dry 2 days and then put a coat of original paint over the magnetic paint. It doesn't even look like it's magnetic. I use the tins that have magnetics on the bottom for different spices, colored sugar and such.
After googling different ideas I was unable to find something that would hold spools of thread or bobbins... so I'm rethinking the plastic spool pin thingee that was on the door in the first place. I can still use that, and add magnetic bins or something underneath it.
I finished installing the innards of the 'new' cabinet today, it didn't come with any so I took the metal contraption out of the old cabinet. It works beautifully!