Mike Laverty wrote a book 'Plug Fishing for Steelhead' (Frank Amato books or via Amazon and similar) that answers all your questions and then some. Mike suggests running a fairly lengthy leader (a foot or two shorter than your rod, typically 5-7') tied to a #7 barrel swivel (big enough not to come through your tip top or crack it if you reel up on it). He also exhautively covers colors and raises issues you may not have thought of (e.g. fine tuning the plugs by switching hooks and adding bead chain swivels to some of them to increase the hookp-up ratio, and using a round-eye swivel to attach the plug). It's a short book that's worth reading.

Having started on plugs and now moved on to drift fishing (and some float fishing) the only reason I'd fish plugs for steelhead was the thrill of doing something different. The real skill is working the oars and backing the boat down in such a way that the fish can't easily squirt around the plugs without leaving the hole. Now I'll have to admit it's fun to be in the front of the boat watching the rods when a skilled guide pushes the fish down to almost the tailout and it's 'now or never time' -- either a fish eats a plug or the school shoots up under and around the boat. But it's certainly not as skillful a way from the angler's perspective as is drift fishing or slinging spinners or spoons.

There is one exception that's a lot of fun, and we use it on kings when wade fishing. That's having a partner up high spotting fish and then wading into the run above the hole and backing a plug down on the fish by wading. You get the directions from your friend 'OK, he's moved two feet to your right and the plug's about 6 feet above him'. The play-by-play commentary really heightens the excitement, especially when your buddy cries out 'He's going for it!' about the time your rod lurches in your hands and you rear back. Now that's a rush, but unless you're eight feet tall you can't do that everywhere on most river either.