
Maybe you don't have to worry so much about the swivel attachment.
If you're worried about fitting the striker into the case then you don't need to worry about attaching it to anything (you intend for it to be in the case).
If it's not part of the case kit, any attachment would work with the screw since length is not a big problem anymore.
Maybe a way to attach the small case is more important??
If you do need a connection point, maybe just offer the connection, not the clip.
I had the idea of a terminal connector with a short loop of fine wire crimped into it.
No good pictures of that but you probably get the idea from this image.
Just make a small loop of wire and crimp. They make the connectors really thin too.