I've always spread on the rough side. I think you are supposed to because the spread sticks to it better and you can get more on! Not such a good idea if you are trying to reduce the amount you use.
My only tip is don't spread your ryvita until you want to eat it. I can still see the look of horror on the face of my colleague when she realised they'd gone soggy. She thought she'd been all organised making her lunch the night before.