Brian,

Your best bet for getting more info than you'll need is: vanagon.com. Go to
Mail List Message Archive,
click on Search and enter Retorquing Heads. You'll get 50 results. I usually
search the Archives before I stick my head up. Didn't want leave you
hangin'.

Dan

A thinker sees his own actions as experiments and questions--as attempts to
find out something. Success and failure are for him answers above all.
            -- Friedrich Nietzsche