Teddysmom, I heard several years ago, when Alex Anderson had her quilt show, she said that it is fine to press machine sewn seams open. You would do that on clothing and that holds up. When most quilts were hand pieced, then yes, you want the seam pressed to one side. That said, I do find that pressing to one side makes the section pressed towards stand out more than the other..
I only hand quilt, and use store-bought stencils, make my own from cardboard soda packages, love my pounce.