You guys are recommending a longer board than needed for this guy. 162 isn't going to be as fun as a 159 or 160. I would recommend a 162 to a 200lb person. I mean, you can totally ride a 162, but you aren't going to get the control of a 160 plus the board will be stiffer than it's stated flex since you are underweight for it. If you go with a rockered board, you can do a 158 or 159 easy without losing any float in the powder.
Honestly, with all the camber and sidecut tech out right now, there is no need for lengthy powder boards. The only scenario that I can think of why someone would want a long board for powder is back-country and off-trail powder hunting. Since you are doing a mix of groomed runs, I again highly recommend that you stick with 158-160.
By the way, Arbor makes really great quality boards. The entire brand also looks gorgeous to boot. Very artistic designs.