I would also recommend the improved/double Davy knot. Have used this knot with 6, 6.5, and 7x for the past year and really like it. Simple to tie, especially when it gets a bit colder. Granted I have not caught a lot of large fish while using this knot .... largest was 20-21 inches ... and I had not had a failure yet. There's also a video on you tube that shows how you can use a pair of hemostats that might make it easier (I believe Tim Flagler teaches this method). You are getting lots of good feedback --- good luck!