The island is dismal this year, to put it frankly. Don't forget the entire south island river closure July 15.
I was out there last week for 3 days. Bounced around all over doing water temps and spot checks for steelhead, and searching out new access points.
One incredibly worrying place was the Gordon; one of the last remaining strong holds for summer steelhead on the island. The recorded water temperature for Wednesday, June 26, was a staggering 23.7C in the lower end - 16C in the headwaters. Unfortunately the fish are all stuck in the cesspools down low, unlikely to be able to move up until fall rains.
Another well known one, that unfortunately isn't part of the July 15th closure - The Nahmint - was already at 18C, and had a severe lack of fish for this far in the season. 3 of 4 holding pools I spot checked that always have schools were completely void, only one had a measly 15 fish.
In short, my little scouting mission made things certain - the fish are in real trouble this year. The conditions are dreadful, and are unlikely to improve, and the runs are the lowest I've seen in my 8 years of exploring remote places.
My advice is that you'd be better off going elsewhere, or beach fishing pinks. If you're dead set on the island, focus on north island glacial melt systems, and far west coast glacial melt systems. Anything around alberni/west will be a write off for any ethical angler - make that any system that doesn't drain from a large, high elevation mountain range.