I'm sure you already know that Blackmouth like structure ,ony serious dropoff ledges where bait fish can hide behind during incoming or outgoing tide -that is where you want to be .... I would target depth areas from 70-140' no deeper than that .....
also if you can find bait fish that's where you will get chinook . (besides sonar look for birds and seals)
As far as gear : 11" flasher green with red stripe or green /silver 25' behind downrigger ball and 40-42" leader with either Red racer candlefish, 3 1/2" - 4 " spoon ( irishflag,cookies&creme) or fresh herring . Fish the bottom 10-15' or look for suspended bait .As far as speed - 3-3.5Mph ,wire angle about 20 - 30 degrees from vertical at the downrigger pulley .....
Sometimes it is wise to ride and keep checking for bait than keep trolling for hours and hours

That should win you some $$$$$$$$$$$$$$$$

.... Wish I could go ,I'll have to check it out .