[XeTeX] \fontsize second parameter

[Andy Black]

Hello,

I'm new to dealing with fonts in XeLaTex.  I'm using MiKTeX 2.7 on 
Windows XP.

I see from the LaTeX2e help documentation that there is the 
\fontsize{size}{skip} command.  I understand that the first parameter is 
the font size in points and that the second parameter is the line 
spacing.  I see that Computer Modern typeface uses 1.2 times the font 
size for its value of the skip parameter.

For my purposes, I'm converting an XML representation of linguistic 
papers to XeLaTeX.  A user may say that a given piece of language data, 
say, is to use the "Charis SIL" font at 12pt or they may say to use 
"Abyssinica SIL" at 14pt or Scheherazade at 20pt.  This piece of 
language data may appear within the text of a paragraph or as a cell in 
a table, among other possibilities.

My question is: what value should I use for the skip parameter of the 
\fontsize{size}{skip} command when switching to these fonts?  Will 
multiplying the new point value by 1.2 be correct?  Or is it actually 
font-dependent and, if so, how would I know what value to use?

Thanks!

--Andy