What is the difference between the Braca IV and the Braca XI Van Dusen '92?

I guess nothing more to add from the title.....what are the differences between the two Braca paddles that are most commonly used in surfski paddling: the IV and the XI?

Thanks in advance. 

They feel a lot different, and you may see why, if you compare:
paddles.braca-sport.com/paddles/kayak/braca-iv.html
paddles.braca-sport.com/paddles/wildwate...sen-92-surf-ski.html

My thoughts:
The XI is wider at the end and not as wide close to the shaft, which provides a more instant and powerful catch, and also allows more flexibility regarding the sideways angle of the paddle, which is an advantage in waves and allows you to paddle with a lower style when needed. 
I have found that while I use a 45 degrees feather angle on most other paddles, I have the XI on 40 degrees.

Thanks, I did check out the specs of the paddles, but I was more thinking in the line of what you described in the way of feel between the two.  Both in calm and surf conditions.