v3 missed 3 of the 4 fixes I requested. I would like to commit the attached simplified version of v3 that includes all fixes, leaves txtfont global as a list, and uses subscripting consistently instead of .config.  But I would first like confirmation that this version works well enough on Mac to do do.

Ned, with this binding, (ignored on Mac?)
        widget.bind_all('<Control-MouseWheel>', self._updateFont)
plain wheel moves scroll as desired while Control-wheel changes font sizes. This is standard behavior on Windows.

I am not sure a menu entry is needed, but if one were added, you are right that it should follow Serhiy's menu patch

Serhiy, a question partly for you: various places specify a tuple when a font is specified by family, size, style. By experiment, tkinter.font.Font requires a tuple for such a sequence. However, a list seems to work fine in 2.7 and 3.x when setting the font attribute of text:
   text['font'] = txtfont 
Does tkinter or _tkinter convert to tuple? Can we depend on this, or is it an accident? To  be safe, for now, I am leaving tuple(txtfont), but I wonder if it is needed.