If you are comfortable using hand tools, and can follow often obscure service documentation, your best bet is to do the work yourself. If the bike needs repair that you find intimidating, you'll be at the mercy of whomever you take it too. I doubt any of the shops in the Seattle area are familiar with anything Norton 961 related. The boutique motorcycle shops in the South Seattle area would probably be glad to take your money, but they would be learning to work on the Norton just like you would be if you did all the service work yourself. Plus your bike would end up in service jail with a pack of kids for who knows how long.
I live in NE Seattle, but I don't use professional mechanics myself, so can't help with who to take it to. I could do it, but I'm retired, busy not working, grumpy, and allergic to people. Basic service is simple. You just need a lot of tools and some patience getting familiar with the bike. Get a rear stand, a low profile long oil pan, the service manual, and beef up your tool collection. The guys in the 961 forum here can probably help more than a dealer mechanic that has never touched a 961, or even one that has.