Test the fit at a local store
I have been using green for a year now, love them and they fit great. I had a thought that perhaps it was a bit too high of an arch though, so I tried blue. I use F (11.5-13 M) and have a size 12 foot. I find the green to fit perfect, and the blue to be too narrow in the heel. As for the arch support, exactly as you would expect, just a bit shorter than green.