Update:
Supposedly you can accomplish this by right-clicking in the tiny gray area
surrounding the reading pane window and choosing 'text size' but...you
guessed it...it does nothing.
*sigh*
> I have a high-maintenance user who wants to increase the font size of the
> text in the reading pane and for the life of me I cannot find info on how I
[quoted text clipped - 3 lines]
>
> Thanks in advance.