It varies a bit, but a good rule of thumb is a foot of drop per second. I'm not familiar with that hole, but standard protocol would be cast upstream towards the head of the hole, and give it slack line for 25-30 seconds(if it's 30 FOW) then retrieve as slowly as possible while keeping the blade turning as slowly as possible.
And if they have lockjaw, use as small a spinner as you can make work in the current. If it was me, I'd be the idiot tossing a #2 or #3 on 8# line. If they're not biting big stuff, try small and subtle.
Warm water and Chinook can be a tough gig.