i thought i told you about this concept early on but i may not have being the space case i am. I have one in delrin round stock that Dave London whipped up but it needs some work in the slippage department.
but this shape would work - as long as it didnt crack over time from flexing
It belongs to the famous Clifford L. Kraft wonderful guy and great nickel carver.
His website is
http://www.paulbunyan.net/users/pckraft/index.html
check out his work and enjoy.