Jerry, there are some pretty good posts here by collectors/casino employees from France, Germany, Belgium, Spain and Monaco, who cover most of what you are asking... and more. Also, Katie Smith, has covered the breakdown of plastics here and their components. All pretty good stuff, especially from the one gentleman from Monaco who discussed storage.

I had sent Jay two plaques that were sent to me by R. Anthony Valvo, who had coated the lunettes with a marine varnish -- maybe Jay can exhibit them.

Quite a bit to read, I'd say, by some folks who gave it their all in explaining most of what you are asking here... and, last but not least; Thomas C. Day covers quite well the destruction of Monte-Carlo plaques by washing them in his A.NA. Numistmatists articles at our Museum of Gaming History.

If I think of anything else I will be sure to tack it on here.

Happy study... 😀