I think vertical would be easier to get one or two fabrics out at a time, but I have mine stacked horizontally. I made sure we built my new shelves very close together so my stacks of folded fabrics can't be more than about 8" high. That way even if the one I want is at the bottom (and it ALWAYS is, darn it!) I only have one small stack to pull out, remove the piece I want, then slide it back into the space. I'm seriously considering trying to design some sort of giant "tongs" that would allow me to smoothly slide just one piece in or out of the shelf without disturbing all the rest of the stacks.