Considering nobody has answered yet, I'm going to have to give the most educated response as my inexperienced self can give.
Normal board is easier to maneuver but with your size 12 boots, there's a good chance you're going to get some overhang in the toe department. #1 it'll look stupid #2 when your turn sharply, your toes could catch in the snow, creating drag, and nobody wants that.
Wide board will float better in powder and will be more stable at high speeds. however, edge to edge response will be slightly slower than regular, but it's so fckin slight that it doesn't matter. If you ride mainly park than it might matter, otherwise not at all. If that's the case, than you may be okay by going a little more outwards with your stance 15/-15 as a minimum.
I have a size 10.5 (163 lbs) boot and go wide board (160 cm) because it fits my riding style. Turns are not a problem at all.
If you look at this vid, you'll see that the diff it not exuberant.
YouTube - The Purpose of Wide Snowboards
basically the idea here is to go as thin as possible without getting overhang. Some regular boards are wider than others.