Ah I think we are misunderstanding each other.  The "Magnetize Clothing" poses do not actually add magnets to the conformer.  They set the magnets in V4 to affect the conformer.  While channel dials appear in the conformer after you run the "Magnetize" pose, the real change is happening in the conform TARGET (V4).  You can see this clearly in the Hierarchy Manager window.

In short, nothing for you to do there, it's handled.

edit: if you DO see magnets in your conformer, they were added when you applied the donor rig, as Jules and I thought you meant.

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