My standard trace setup for 25-50Lb is:
Line from reel -> aussie plait -> double line -> snap swivel
Then, when specifically targeting couta (or using rappies), I have a separate trace which I prepare at home and have coiled up in a zip lock bag, which consists of:
swivel -> uni knot -> 80 Lb mono leader (about 1 m) -> Albright knot -> No 5-7 american piano wire (+/-25 cm) -> haywire twist -> snap swivel -> rappie
Been testing and using this for a year know... after a few discussions, and actually seeing it underwater, I realized the double line opens up and creates some commotion that may scare the fish away (or not!)... so I wanted a single leader as close to the lure as possible...
After about a year and quite a few couta, tuna and wahoo, I have not had a single failure on this setup. I don't think my hook up rate is lower than using a wind on leader directly attached to the lure (have experimented this with peterblace - he uses no wire at all)... in fact I lose way less lures due to the razor gang!!!