Re: Tieing fly line loop to new leader
I'd also suggest a perfection loop. I've literally tied at least a couple thousand of these loops over the years, and have never had one fail. Very simple and fast knot to tie once you figure it out. If you play around with it a bit, you'll also find it's very easy to adjust the loop size to suit your preference. If you do happen to mis-tie this knot, it will be immediately obvious once you go to tighten it.
To be honest, I also tie a loop on the tippet end of my leader and use a loop to loop connection to attach my tippet. Granted, I do tend to fish a long tippet, 2.5 - 3' so the loop to loop doesn't in any way interfere. A leader pretty much lasts almost forever.