As stated, these fish have been in the river since June/July. The water is low and clear, the big heavy lures with mainline of 30 and leader of 25 will never catch a fish in this water unless of course you snag them, which is probably not what you want to do. When I fish the cap in the summer and the water is low, I use a 6 pound leader max, usually 5. With that leader and the low water, you can pull out a 10 pound fish pretty easy. There is no current for fish and the fish will not go around bends in the river because the water is so low, that only some pools remain and the rest of the river is like a creek. I have never had a fish or seen a fish out of the cap take someone around a bend. And no the "sharp" rocks will not cut the line, never seen that happen, unless the fish wrapped it's self around a boulder in the water or something. Most of the fish in there right now are between 3-6 pounds in the river river now (coho) and the steelies are bigger. Bigger fall run fish will push in with the rain.
You probably will not see springs in there that much until the water comes up, mostly left over hoes that are LOCK JAW due to the low and clear water, these fish are stale and have been in the river a few months now. Using a 25 pound leader is just over kill, ESPECIALLY on the cap. If I would fish gear, an 8 pound mainline and 5 pound leader, small spoon or spinner, first and last light. Fly fishing, like I said is your best bet because it does not spook fish as much as metal falling into the water. Even when fishing the Vedder, Chehalis or any other lower mainland stream, I will run a 8-12 pound leader max, no need for 25's and 30's at all.
Fish will bite if they do, probably not with the water being as it is, but you do get the odd one, you gotta work really hard for them when fishing gear. They will just sort of chase your lure, open their mouths and hit it. If you get a chaser don't be surprised if they turn away at the last second, cap coho do that a lot. Like I said, the water is low, clean and fish are stale, wait till it rains for fresh, biting fish.
There is little current on the cap right now, so its like playing a fish in a lake almost, so lighter line and you won't have a problem landing a fish.