[Otto]

Seems like using Dzus fasteners attached directly to balancing weight clips would work, so you could use the WalMart aluminum pizza pans for ~$4 each.

3 Dzus fasteners per wheel, each attached to balance weight clip. No ring needed. How light and inexpensive could that be?

Or, instead of aluminum pizza pans, or expensive Lexan, use PETG plastic, which is vastly stronger than plexiglass and much more impact resistant.