I think in most cases hi viz yellow, especially the thinner it is like 4lb and 6lb test will not spook fish at all, want to share a real experience with you, on Clarks Hill about 2 years ago. Me and Dad were long lining one morning using the same baits and colors, I had Crappie Maxx 4lb Camo on my spinning reels, he had Crappie Maxx 8lb hi-viz yellow. The count at the end of the day was my 50 to his 2. I tried slowing down to get him deeper thinking that was the problem, still no cigar. It convinced me without a shadow of a doubt that thick hi-viz yellow in clearer water definitely can make or break you. We generally are about equal on catch ratio. Needless to say the next fishing trip, guess what wasn't on his reels. I am a huge fan of Crappie Maxx Camo, it does get the job done, so it seems the thinner hi-viz yellow does too. Clearer water applications with thicker high viz yellow line can be a bummer. Most lakes around here have good stain to them and nullifies this problem. For me it's the Camo and 4lb test for extra insurance. I have experimented with Trilene XL 10lb test clear on baitcasters long lining and it does a good job, it's diameter is equivalent to Crappie Maxx 8lb test. Anything thinner than 10lb just doesn't work right on a baitcaster when casting it will have a tendency to want to bird nest with you more easily, anyways that's my 2 cents. Good fishing!