I normally ride boards in the 24cm waist range and I used to have very bulky size 10 boots. Those were from 2008. Any newer boot will likely be lower profile than my 10's.
Now, you have to consider this... the waist width is the measurement at the most narrow point of the board. Your feet don't stand on this point. Your feet will be sitting on top of the binding inserts. The board is actually wider at these points.
Also keep in mind that angles also affect the overhang. If you have a ducked stance, the more angle you rock, the less overhang you will get.
Moral of the story? I'm 90% sure you're good to go. 10% unsure because different overhang strokes for different warthog people.