Hi there everyone,
After much reading and deliberation on wide angle lens and filters to go with it, I got the Lee holder with the wide angle adapter, and Canon 16-35mm II lens.
My biggest concern about this combo was the vignetting, and here's the results of the combination.
Shot with a 5D II and 16-35mm II, with Lee Holder, wide angle ring and 3 filter slots on the holder.
(Please ignore the bottom part of the images, some shadows going on there. And the bottom right corner has a shadow too)
Apart from the WB there doesn't seem to be much difference except on the one shot at f2.8, but that's the normal vignetting of the lens.
Hope this can be useful to anyone 
Cheers.

