What knot do you use? Surgeons Loop vs. Perfection Loop vs. Lefty Kreh Loop

[Lowhydrogen]

Lefty and the knot that bears his name are almost unknown outside of the fly fishing world.

You're right about that, and it's a shame too, a lot of his contributions/ideas have a lot of value even outside of fly fishing. I threw deceivers below small sinkers to deep Redfish on pilings once when I couldn't get them down with a sink tip and had a blast (don't tell anyone). I have mostly been a saltwater spin and fly guy, and Lefty was one of my all time heroes (still is).