sound in revolution

[Andrew]

Hello, List.  I was just wondering where I could get more information 
about dealing with sound and music in Revolution.  Maybe someone could 
answer some of my basic questions or refer me to a very simple, 
beginner's tutorial.  (Well, not too beginners. I know how to import a 
sound and play it.)
1. What's the less expensive sound file in terms of space?  Wav?  Mp3?  
Any considerations for short or long samples?
2. How do you play/stop/open/close MIDI files from inside Rev?
3. Has anyone heard of .nsf files?  Can these be played with Rev?
4. In HC we used to be able to change the pitch and tempo of a sound 
file.  We could also play sounds on different "channels".  Is there a 
way to do these things with Rev?
Thanks so much
-A