for me, the ends of the pillowcases extend to the edge of the bed, no matter what size the bed is. i think it is really personal preference. if i received a pillowcase with a decorative edge, i would just place it whichever way shows the decoration. i don't think it matters which side the seam is on. if i had to choose, i'd put the seam at the top so it would not be felt near the neck and shoulder if i were to raise my hand there.