My client wants to have the following shipping rules apply but I can't quite figure out how to implement them.

Store is based in Seattle and all products should ship with the same rules (all about the same size/weight)

Shipping to Washington State should be $4.60 for first item and perhaps add $2 for each additional

Shipping to the rest of the USA should be $7.50

Canada and Foreign orders should have USPS Priority Mail International as an option (Already Setup)

I have a feeling I need to setup zone rates. However I'm not exactly sure what settings will allow the desired rates.
I suppose the calculation method should be "Item"
Skip Countries: Do I need to input all except the USA here?
Zone 1 Countries: Currently zone 1 is the US & CA however I don't want Canada to receive these rates. Do I need to modify my zones or just remove CA from Zone 1 Countries?

Shipping Table: Not sure how to represent the necessary logic from above here.
If I put in 1:6.50 is would that be the same as $6.50 for each one, or is it $6.50 for the first one? so I would also need 2:8.50,3:10.50,4,:12.50 and then hope no one wanted more than 4 or whatever number I stopped at

I apologize for the rudimentary questions but do appreciate the advice!

Thanks!