I don't wash my fabrics as I find out if the fabric is going to bleed when I put it in my tub of starch. Just had 2 batiks bleed like a stuck pig on me too. Tried the blue Dawn dish soap as someone mentioned for new fabric dyes this will stop the bleeding. It didn't so went to my Bubble Jet Rinse and that seemed to do the trick. Plus after I've pressed it I figure if its going to strink its probably already done it between the starching and pressing.
As to the sateen, yes, it does have a nice sheen to it as well as a nice feel to it. I tend to grab any sateen backing scraps from one of my local fabric stores. Use the scraps in my quilts and the larger pieces for my backing. Nice drape to it.