When you say pixel fonts... do you mean bitmap fonts (as opposed to TrueType or Postscript fonts)?
If so, remember that you can no(*) control over whether a font is (or is not) installed on a client's web browser/system.
If you set the font to be XYZfont and they don't have XYZfont installed, then they will not see XYZfont (at any size) - instead the font will be replaced (based on CSS settings) until finally a font is found that is installed.
(*) - with the exception of embedded fonts which is an IE (windows?) only technology where the font is converted into a proprietary format and made available to download (like a CSS is included).
Jeff