Thank you for the offer, I'd happily buy some coffee to make it worthwhile for you. But I'm hoping that won't become necessary because I'm now thinking that maybe the solution is simply changing the site files to expect UTF8, per these instructions:
https://www.zen-cart.com/content.php...8859-1-to-utf8

Of course, because my db is already expecting utf8, I won't need to run that mod... just change language and config files.

I'll give that a quick whirl, report back.