Thanks for a reminder about TT. I'll try it immediately, if not sooner!
Discovered that I actually have TT System
4. It was out-of-date, so I updated it. Unfortunately, I did not see any place to set a font size for Safari. Nor did the new version seem to recognize my previous registration.
I also have a version of the simpler TT (V.4.9.5). I've attempted to set "Application" fonts to 16pt Helvetica. A restart of Safari is required. That app was also out-of-date. The new version requires Sierra!
I also found a TT System
5 version. It also requires Sierra!
I also ran a version of Cocktail. Set the Safari Standard and Fixed-width fonts to 18 pts. I'll Quit/Open Safari and see if I can "see" any changes. ...Possibly. Zoom was also changed back to 115% before I started post this, anyway.
I got other irons in the fire... will work on this later.