I use two pair, one with copper and the other with the darker grey tone. The copper is better for moderate light while I much prefer the darker grey in high sun.
Everyone's eyes are different but the grey gives me much better color recognition and the copper gives me better contrast in low light but puts an off color on things.
Something in the way I see cancels out reds when wearing rose glasses - brake lights don't register as well while driving. So although favored by many I stay clear of roses and ambers while driving.
Everyone's cognitive patterns are different, I trust color and movement more than shape (which is almost always very distorted). Movement can be very subtle so color is a key identifier for me and sometimes the one factor above all (depending on the day).
I would recommend contacting Action Optics. These guys are both fishermen and optic experts.
IFFF Certified THCI @ 2005
Capeflyfisher Guide Service
Island Hopper, Guitarist, Incurable Dreamer
and Founder, Worldwide Flyfishing Forum