Just an update on my initial question. I took Kate's advice and cut a square of the silk satin. First I steamed it using my new iron, forcing lots of steam into the square and then letting it sit until it was cool to the touch. I carefully measured the square and it had not shrunk one bit. So I then soaked it in tepid water and gently squeezed out the excess water. I pressed it while it was damp (as I had read about in one of my books) and again, there was no shrinkage. So, just to be safe, I'm going to steam the entire yardage and go from there.
Thanks for everyone's input. It was an interesting exchange. By the way, I love my new iron and so does my husband because I pressed all of his clothes for "practice." :-)
lisa