Gees, Chuck. I can't believe you mentioned George Harvey. He immediately came to mind while reading Neil's article. You beat me to the punch. I once read that George Harvey never felt it was necessary to use any tippet smaller than 4x for nymphing. I'm not sure about his thoughts on dry flies. Even though I know that, I can't make myself stick to 4x in skinny water. I always go to 5x for nymphing during the summer months thinking it won't spook as many fish in the clearer water, but I think 4x would be just fine. How about you, do you nymph with 4x in skinny water?
Bruce