I know how to tell the whole page to use the same font size using CSS, but what I'm needing is something different.

As all of you probably know, different browsers read font sizes differently. For example, IE's 12pt looks like Firefox's 14pt. What I want to know is if there is some way to dictate how browsers display the font. Is there some way to universally regulate the font size?

Yes. Print the pages. On the screen, no.

See also Web pages aren't printed on paper.