I am kinda picky about this topic for flats flies. Dor certain flies I not only want the right color but a particular brand due to reflective, adhesive and diameter range.
For baitfish flies I prefer a silver-based with black pupil, just because that what the baitfish themselves have.
I think colors in the eyes of saltwater flies do play a role in mid-summer mid-day conditions, however as I always preach not nearly as much as the mood of the fish (based on what's going on at the time) and the presentation. Not too many things can be off when sight fishing during the dog days least of which the scenario you are staking out.
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