>With today's silver price, that would be around 25x$8B, or $200B worth of silver to let our current change convert to constitutional money.
Sorry, it doesn't work that way anymore. With a few outliers, American silver coinage was 90% silver before 1965. Today it is a sandwich made of baser metals and not worth face value, save for the penny which costs 3c to make.
The charming thing about "junk" (90%) silver coins is that ten dimes, 4 quarters, two halves or a silver dollar all contain roughly the same quantity of silver, about .715 Troy oz.
https://learn.apmex.com/learning-guide/bullion/what-is-junk-silver/