[OS X TeX] Font sizes

[John B. Thoo]

Hi, everyone.  I hope this question isn't too off topic for Mac-TeX.   
I'm using TeX Live 2007 on my PowerBook running 10.5.8.

I would like to place the letter X about 0.5 inch in height in a  
pstricks environment.  This is what I've tried.

\begin{pspicture}(10,5)
   \rput(2,3){\fontsize{0.5in}{0.7in}\selectfont X}
\end{pspicture}

But I get these warnings even though (I believe) I'm using PS CMR fonts:

LaTeX Font Warning: Font shape `OT1/cmr/m/n' in size <36.135> not  
available
(Font)              size <24.88> substituted on input line 2201.



LaTeX Font Warning: Size substitutions with differences
(Font)              up to 11.25499pt have occurred.

  )
(see the transcript file for additional information)


How do I overcome this?  Thanks.

---John.