Just saw your post. Thanks for the starting point, it's definitely some information I would like to start experimenting with. I'm going to continue on with my research so I can make a little bit more sense of how to change f stops using pinhole, but it seems like Fred Parker's Ultimate exposure calculator could be a useful tool for this project.
John- yes, I have heard that a thin sheath of tin or copper (or similar) is used to "drill" a pinhole through, then mounted to the back of the body cap, and blacked out.
Basically each exposure that I make is directly related to the length of a musical piece, (the songs/music will vary) so I suppose what I will need to do is experiment with the aperture mostly, so it can be exposed at the specific length of each song.
Thanks so much for your help- I really appreciate everyone's advice. I realise I'm such a newbie, and it's so nice of you to take some time to show me the ropes.