Also, the Large Burton bindings look about the same length as the Unions in the same size, if not then longer.
If you're foot size says 14, it probably is. Different brands have different sizing. I should have checked this before getting my boots in size 14:
Before trying on a new pair, make sure you've been walking around a lot that day so that the blood in your feet is circulating well and they've "expanded", because that will happen while snowboarding and will help make sure you don't get your boots a size too small. After this, when you try on a pair of boots for the first time, your toes should be just touching the ends. There should be no "extra space" between your toes and the liner; they should just fit snug, but not so you're in any kind of discomfort. Over time, the liner should loosen up a little and give you some extra room.
No offense to your boots...but DC is a pretty bad brand for anything involving snowboarding (in my opinion). This is because they try to make all they're products feel more like skateboarding, and always try to relate and make snowboarding more similar to skateboarding. They just don't get that snowboarding is purely it's own thing and they can't take that away... and their stuff isn't very durable from what I've seen in reviews! If you can't find better boots though, they should be fine!
I hope that helps.