I mainly fish the Columbia River, fishing in hoglines (where boats are all lined up abreast in 11 - 60 ft.deep water, with additional hoglines upstream and downstream that must be avoided once you hook a salmon and release from your anchor, motoring either shallower or deeper to the main channel with the kicker while fighting fish trying to avoid them). We back-bounce a 6-16 oz. lead on a 2-4 ft. dropper line from a slider or 3 way swivel and run a 3-5 ft. leader back to the lure (K-14 Kwikfish or herring for spring chinook, flatfish or spinner for steelhead & salmon shallows and big wobbling spoons - Clancys, Brad's Wobblers, Alvins etc. for the big hog chinook of the fall run in the deeper water).
I grew up using 20 lb. mono... and big fish can be caught on it... but how many 35 lb.+ salmon are you really going to have a chance at in a lifetime? How many do you want to watch swim away if a seal comes or they wrap around an anchor line below you? I use 65-80 lb. braided PowerPro (bright yellow- high vis) or Tuffline for the mainline and 40 lb. mono Ande for the leader. The braided transmits every wobble of those lures. You can see when a small weed hits and hangs on the hooks of one (telling you to clean it) as well as how and where the fish is swimming. Braided transmits a delicate sturgeon nibble better too. Salmon and steelhead are not leader shy here in the big river, go big and go home with fish. In the smaller, clearer tributaries, guys use lighter leader. I won't use Fluorocarbon anymore... for leader or anything, I've seen too many fish break it unpredictably.
I rarely cast anymore, and know some guys prefer mono for casting. I know we hooked a monster 36 lb. chinook a few years ago on the light summer steelhead rod rigged with 15 lb. monofilament. We got it in.... 2 hours and 20 minutes later... it was fun, but how many others did we miss while drifting downstream fighting that because of the light gear?
CW
Satisfaction: 23' Aluminum Thunderjet with Ford 460 salmon fishing the Columbia River