On average my ultra best king time for Sekiu has been a week after the fourth. They are around the first but it often times is a week or so early for the big slabs. However you will be hard pressed to find a clipped slab although I saw one last year over 40.
This last question will lead to a zillion responses. What to use.....I mainly mooch cut plugs along the kelp beds. 20 feet down at dawn and dusk. Deeper as it gets brighter out. Although the short opener a couple years ago for both clipped and non clipped I absolutely hammered them several days in a row in 200 to 250 feet of water 30 feet down. If you have a fish finder use it to find the bait. If I haven't caught a keeper I will then put out the downriggers and troll a flasher/squid/herring strip combo and a whole herring in a helmet starting at 70/90 feet and working my way down to right off the bottom in various depths to 200 feet. I usually didn't have to resort to the downriggers at Sekiu though until it went to clipped only.