Now can anyone tell me of an earlier use of this method?
Electrum wallet has had this feature built-in since version 2.0, released in 2015 if I'm not mistaken, so the method existed at least five years before your message.
And if you carefully read the Electrum 2.0 release notes, you can find out that they based that feature on Andreas Schildbach's base43 idea, which is even much older (here are some sources from 2011: [https://groups.google.com/g/bitcoinj/c/oEOtluuyQBo/m/KBven3k9LzEJ]).
So, I'm sorry to disappoint you, but no, you are not the "originator" of that idea.