I am looking at the same type of skis and I am of a similar build. The B3 is supposed to be the best of those 3 and the most expensive of the group. There are deals on the other two to be had on the web. My buddy skied the AK luanchers in Whistler and loved em. They have constant deals on Little big fats on ebay which are a similar ski and check out the Stockli DP's they have on Ebay for cheap right now.
If your going to be doing any hiking at all forget the Fatboys they are way to heavy. As I recall they are close to 12 Lbs a pair. Thats not bad if you are lift served skiing. Great for busting crud but not so good for Back Country hike to skiing. I'm not a big Rossie fan The B2 and B3 give littel feed back. For me they seem lifless and were rather ho hum. I have skied the K2 Launchers a couple of years ago before they added the Mod dampening system. They have good float. Nice feel for the snow and a good even flex. They are a forgiving ski. Not as demanding as some other skis. They would make a good ski to use with an AT binding system
I don't hike as much as I used to I really just gravity-poach over mtn. or off the side. If there is a naked bowl though you can bet a buffalo nickel that I'm haulin a$$ to get there... But not in my K9 boots, that would hurt!