Ok so I might have a solution for a DIY adaptator.
You just take one like these and cut the "ring" part of the peg (in red on the picture) and the little molding left over on the top of it.
Then you could use a dremel to dig a hole and glue a magnet in or just use some electrical tape to add a few layer of thickness to the peg so it hold the headsculpt nice and tight.
I suggest to add a layer of electician tape over the magnet too if you go that route to make sure you have an extra protection so the magnet doesn't unglue and get stuck in the neck of the headsculpt.
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