It depends on your boot, but it's a tough call because you fall right in the middle. Honestly I'd suggest going with the L/XL because the toe strap length can cause pinching issues on the sides of your toebox if you like to strap in tight. Only problem is the larger chassis will leave room for some lateral freeplay within the binding, which is why I've gone completely away from Rome's metal bindings after owning and loving several pairs of 390's and Targas over the years.
16 NS West . 15 NS Snowtrooper BIA . 13 Salomon Pow Snake
15 Now Drive . 14 Burton Genesis
14 Flow Hylite