I'm 6'4" and 190lbs and ride around the 161-163 size. My boots are about 11.5 too and I go for a wide board so my toes and heels don't drag.
Depends on your setup though, some boots have a smaller profile and boards vary in width. Your stance also affects whether you overhang or not. I read that it takes a lot of overhang for it to matter and maybe others can give better guidance here...
What type of riding do you do? That will affect which boards you should look at.