Hi,
These are two different things: font and font size. So you can try to troubleshoot them separately.
If the converter does not use the font you specified, check whether the font is a true type font, and whether the font is installed on your server. For example, if you run the converter on your web server but your web server does not have that font installed, then it won't work ---- even if your client machine has the font installed and can display the font perfectly fine in your browser.
Once you get the font working, you can troubleshoot font size. Most of the time the font is small is because the converter auto-scaled the result, not because it did not recognize your font size settings. You can find more information about auto scale here:
http://www.essentialobjects.com/doc/4/htmltopdf/auto_fit.aspxThanks!