i usually use 60-80lb black magic supple trace for a shock leader about a length and a half my rod unless im fishing the pier in brightion then i use one that i can have the line on my reel while the fish maybe in the water . usually tied with a no name knot or a knot similar to the lethal or albright knot. i find a back to back uni is too large of a knot
I use the improved albright knot, hell i can tie that sucker with my eyes closed i’ve done it that many times, and no not because the knot fails but you do have to keep an eye your knots from time to time and re tie when necessary. And like you ginga i use black magic supple.