David, the first thing you should do is get more Delrin and make new posts.
To ensure a good seal between the Plexiglas ring and the plates is to take some spark plug boot silicone grease and coat the edges of the ring with it at time of assembly.
You will need to eliminate all friction. If you've not done it, already, loosen the bottom plate to eliminate all compression and then spin the flywheel. It should coast freely for many revolutions. If it doesn't, find the problem and fix it.
Best regards,
Orrin