I used clip-ons that I altered so that they would not "pinch" (magnets can actually do some damage on the cellular level). As for the earrings themselves I used Model Magic to make the "disks". Prior to drying I made holes just large enough to allow the clip earrings to pass through so that they could hang naturally and shift with head movements. After having them dry I applied some high gloss spray paint to both the clips and the earrings and then combined them to achieve the final result.
Model Magic, when dried, is featherlight in weight so it should not harm the lobes of the ears- even for disks as large as the one she wears.
I made my San costume way back in middle school, and only could find one picture of it to post on cosplay.com, but if you want to see the result of my technique it's there on my profile.