RHCE sendmail configuration (m4 or .cf?)

["Benjamin J. Weiss" <benjamin Weiss name>]

I don't use sendmail, I prefer postfix.  However, as I understand it, the 
RHCE exam covers sendmail.  So, since I'm putting in a mail proxy at work, 
I'm doing it in sendmail for the practice.  However, I have a question.

Should I make my changes in the m4 file and "compile" them to the .cf 
file, or should I just manually make them in the .cf file?  Remember, I'm 
not interested in "ease", I'm interested in experience for the RHCE exam 
I'm expecting to take in January.

Thanks!

Ben