Anyone putting decent mileage on the Nike Air Zoom Katana Racer II? I was wondering how that forefoot holds up. Also, I'm in between sizes -- my regular size feels a little snug (fifth metatarsal a little smushed, big toe almost touching), but I'm afraid that the half size up will be too sloppy (big toe more than thumb width from end). Does the forefoot fit loosen up over time so that my regular size will be fine? Any other thoughts about the shoes? Not many options out there with a low heel, narrow heel, and some room in the forefoot.