So I've got a burton clash board, and one a size 11 boot. From what I've read the 10 and 11 boot sizes are pretty awkward because you may hang over too much on a regular width board, and be too small for a wide one. My heel side boot hangs over about 1.5 inches, but e heel curves up for the last 1/2-3/4 of an inch. My toe side hangs over about the same amount, but has the gas pedals so it seems as if I'm in the clear there. Opinions on wether or not I'm going to experience toe/heel drag?
I have about an inch and a quarter on each side and it's never been a problem for me except steeper hills when it's slush or powder I'll notice some drag. But I've never wiped out as result of it. If you doing super-deep carves, then that changes everything because when you really get your board up on its edge that's when those overhangs can be a problem. But I'm not laying down any of those crazy carves so I'm not worried.
Put your boots on your board and strap them in, then tilt it on each edge and that will give you a ballpark idea of how deep you'd have to turn before it became a problem. I'm guessing you'd probably be fine without a wide board, but there are a lot of folks here who could better confirm or deny that statement. Like I said, never been a problem for me to date.