A paperclip hehehee.(i'm pretty sure that even wire from a coat hanger is thinner than 20g, let alone 18g, just so you kno)
i used 18g kanthal and 24g SS430, but 20g will be okay as the bridge.

And Thanks
EDIT: I wouldnt see why you can twist some wires together to make something thick enough for the bridge part, come to think of it why not do that and make the
coils twisted aswell !? LOL
i'm sort of toying with the idea of doing the other build that doesnt show the
coils glowing.