Need help to mount these

Pishta your right about interference fit on the rear really I should have got a different style but I liked these also don't really want to apoxy or magnet as they never stay on and although they had only five left so I bought them all to have a spare I was thinking of maybe a thin ring that could screw to the back of the cap then go under the lugs like the spider cap and paint that part black to keep the clean look....the trick is how to make them? Thanks for the ideas keep them coming please.