Hello David,
Thank you, I think I need to read that NIAE report a couple more times. Am I to understand that these earlier models may not be as well constructed and potentially prone to premature wear or failure? I appreciate your connecting me with Webhead and Wallfish as well. I will be in touch with Webhead shortly to pursue the diaphragms. I was also able to find a couple Champion UY6 plugs and have them on order.
Thanks,
Clint