What fuel mileage are you seeing on the 600 Pros? I’m asking because once a year we do a 1,000 mile trip somewhere in northern Alaska and we must haul all of the fuel. I’ve been using a 600 Etec Summit which gets about 15.5 mpg, breaking trail and pulling a 700 pound sled. I’m thinking about buying an ’13 600 pro to replace the XP.