I went to Nitto All-Rounder bars at 490mm since I'm very narrow and I wanted an almost straight back sweep but my clamp is 25.4. I don't think that one comes in 31.8. You could use the Nitto mustache (or any other brand, actually) and install it with the rise up. There should be a bike shop where you can take your bike and they can put different bars on for you to try out.