Ray,
Check this site; may be what you're interested in:
http://forums.catskillflies.com/inde...m/4-fly-tying/
Some beautiful flies come from there and are an important part of our flyfishing heritage.
Having said that, I do a majority of my fishing out west in some pretty rough water and a lot of the dries I attempted to tie in the "Catskill Method" ended up being very pretty wet flies in the heavier flows (could be that I wasn't tying them properly). Many of those synthetic materials - foam, polypropylene yarn, synthetic fibers greatly improve floatation for my flies. Can the fish tell the difference in the materials? I don't know, but if I can see it, I can fish it better. Just my 1/50 of a dollar.
Regards,
Scott