It took me about a day to get used to the the font size in Cinema Display. Now I found the text size too big when I work on my MacBook Pro (15-inch, early 2008 model).
Have you tried temporary zooming?
Simply move the mouse cursor to the areas you wish to zoom in, then hold down the control
key and scroll up on your mouse (or two finger scrolling up on your Apple Magic Trackpad). To return to original zoom, hold down the control
key and scroll down.
Those settings are under System Preferences | Universal Access | Seeing (tab), and the Options... button under Zoom section.
Note: both displays will be zoomed at the same time (if you use multiple displays).
UserAgent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:220.127.116.11) Gecko/20110420 AlexaToolbar/alxf-2.11 Firefox/3.6.17