Just to add my .02 I use froghair because of it's versitilty
this stuff is limp!! and with it I can cast and float very small dry flies even though it is heavier than water (I think it has to do with the surface tension of water)as well as large stonefly nymphs under water. They hit the FC with gamma rays which allows stretch and shock absorbtion while maintaining strength which is a great combo to me. As for knots I use a perfection loop to attach to my mono loop at fly line and a palomar to attach flies also a surgeons knot with an extra wind works great to add more tippet during the day and for attaching to mono. The real secret is not to heat up the line while tightening the knot but don't get it wet like mono just tie slow and smooth.