I am a longarm quilter, so my issue with bulky seams pressed to one side is a bit different. I've finally figured out that if there are more then 4 fabrics (that will be all in one place in a seam, press it open. If you don't you end up with lumps in your quilt where all the fabric is pressed to one side. Stars and pinwheels are the ones where the center seam really needs to be pressed open to prevent the nasty lump. Otherwise, I press to the dark side unless I need to change that to be able to nest the seams to get a good match up without creating 8 layers of fabric in one place.