I'd suggest that you reverse your thinking a little bit. Don't think about plugging water as much as steelhead holding or cruising water that is amenable to plugging. That means, it's going to hold steelhead for some reason, as in it's a slot, a run, or a tailout. What makes it amenable to plugging is that it's big (long) enough to make the effort worth while, the current is straight enough (not boiling or eddied) so that the plugs will run reasonably straight below you and not tangle, and you can control your boat. In addition to that, if you're rowing, the water has to be moving slow enough so that you can take your time through the hole. Unless you're built like Arnold, this is pretty key. On small rivers and holes, this can be a pain, because you've got to be rowing the boat in the throat of the pool where the water is cruising, to fish the middle of the hole where the fish hold.
The depths you mention are fine, but 80 percent of my fish come out of shallower water. This is partly due to the rivers I fish, but also due to where fish hold. I'd recommend you think more about water that is 3 to 7 feet deep.
I like to fish edges, and I don't back and forth across the river as much as some guys. I wiggle a little bit over the slot I'm working, but mostly I like to march pretty straight down the hole.
If you go to a busy river, you'll get a sense of what most people think is decent plugging water. Look for the guides, and you'll see what is probably good.
For rods, any steelhead rod will work, but the best rod is something that is pretty fast, ie, has a stiff butt, and a real flexible, light tip. I prefer a 7 1/2 foot rod myself, as it's easier for my guests to use to get fish close to the boat. Most folks use an 8 to 8 1/2 foot stick.
A key tactic is to keep the rod angle low to the water, the rod pointed pretty much downstream, no more than 30 degrees to the side, and the drag fairly stiff, so that when you hit a fish, he gets stuck by the hooks. Some folks will argue, but my hook to landed ratio improved dramatically when I did this.
After all this, it's a matter of putting time in on the water, and finding the micro slots in the macro slots. That takes time, reading the water, experimentation, observation, and a little luck.
Go to it.
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