I know it sucks but you do learn a lot from your mistakes. I have designed the new center assembly without the anti backlash because it has bee causing so many people problems and the tension we use it at I don’t think it does anything. Sorry I do kinda feel like that part of your issues was my fault, me trying to fix a problem that isn’t even a problem. Leave it to an engineer to over complicate things.
Hopefully you will be getting it dirty soon.