What type of Tuna are you targeting ? What size reels ? Troll or Chunk ? Do you want to have a little more fun with a lighter tackle like Capt. Tred ,or do you want to muscle them in. In general, braids are not used, mono is, I use 50lb Mamoi for everything on Penn 15KGs(there are many fine quality and less expensive 40 and 50lb tests out there) I mainly fish out to 40 miles off max on my boat so most of my fish are generally smaller than those caught at the Canyons although many large and prestigious fish are caught each season at the tower, bicardi, and the 30 to 40 fathom wrecks. The boat I crew on for Canyon trips ang Nantucket Giant trips uses 50s , 80s, and 120s all with Mamoi. Flouro is used as a leader for chunking (line shy) Again, Figure out what you are targeting and how youre going to catch it. By the way with my rigs on the troll my bars,chains lures etc.. are all rigged with much heavier mono leaders to 150 or 200 wind-on leaders.Although my boat doesn't have Canyon range I'm still go out hoping and prepared for a that oncw a season inshore Marlin, Sword or Big-Eye.