I own a pair of the L/XL Flites and I have a size 13 boot. My boot is a tight fit in the bindings. I think the Flites run on the smaller end of the scale. You would probably do fine with the L/XL.
Oh nice. How do u like them? I haven't gotten a chance to try mine out yet. If they're too small, i think i'll go with the XL.