Automatically set text size to 120% on startup?

[Steve Snyder]

The first thing I do when firing up Mozilla is to set the text size to 
120%.  For some reason, this gets me readable text where setting the font 
sizes in Preferences doesn't.  (This is on a RedHat v7.1 system.)

Is there a way to *automatically* have Mozilla set the text to 120% on 
startup?

A related question: is there any doc on the command line switches, if any, 
that Mozilla recognizes?

Thanks.