Eric,
I too have just recently started targeting SRCs in the salt. I think a 6 wt. is perfect. I have fished Carkeek a couple times with no luck. I have seen baitfish jumping and some larger fish just outside casting distance, but no takers.
Last weekend I checked out Lincoln Park. From what I have read and seen it is a good place to fish for SRC.
There are several great previous threads on the topic, I would suggest doing a search (include archived topics) under "Seattle SRC" or something along those lines. There is also a good article on the front page of this site. Good luck.
Jon