[doodlebug]

Have you considered "beadlock's" and making the tire's tubeless?? silicone the 2 halves (rims) together. Weld up the big holes and use smaller short valvestem on the inside. Run a hose between the inner and outer tires.
Yah, more stuff to make you scratch yer head.
Never thought about racket ball's? let us know how they work.
Cheer's, Neil.