Very close to the same subject was addressed Wed. eve by Kirk Deeter on Fly Fishing Internet Radio. You can listen to him at this link (replay of program): Fly Fishing - Internet Radio
He said the number one thing that spooks fish are shadows from above including fly line (false casts) so the color of the line doesn't matter. He also made reference to the fly being remote from the fly line by the leader/tippet.
According to him you are correct in the fish seeing the red spectrum poorly compared to the blue spectrum better.