16' is massive. I've used a 13' for many years now. I'm a little bloke and I can outcast a lot of people, especially the big blokes with their big rods. Unless you really know what you're doing and find the 16' comfortable, I would recommend the 14' one. It may be shorter but you'll be able to give it a lot more oomph than the longer model.
You also mentioned about the long butt. If it's a wooden butt, then the length is easily sorted there. The few surf rods that I have owned, I have cut and drilled out the standard wodden butt and whipped up a longer one on the lathe out of a spade handle. As I got more experienced (and bigger and stronger) in casting, the longer butt gave me the ability to put a lot more power into my casting.
Anyway, that's my 2 cents worth. Good luck in your choice.