I realize this can be a broad topic, but what size tippet do you generally use for trout that go grow from 10 to 20 inches? I use 4x under normal flows and colored water. When the water is thin and clear I drop down to 5x. I fish central, PA so I'm not speaking of big rivers such as there is out west. George Harvey, the dean of PA fly fishing, suggested that you never need to fish anything smaller than 4x. Just looking for opnions because I'm always trying to learn.