I read somewhere that we quilters press to the side rather than an open seam as in clothing sewing because by doing that it keeps the batting from migrating out of the seam-sort of seals it...makes sense. I have always pressed to the dark side(most of the time), unless that would cause bulk, then flip to light, making sure there is no shadow of the dark, and there never has been (so far). As far as pinwheels, and actually meeting of four corners too, I do the little "spin" to lessen the bulk and avoid the "volcano top"...If I recall though, I think those that do miniatures usually press open seams...not enough room for all those side seams, I guess