I live in Seattle area too. If once blooming is not a problem, Veilchenblau does very well in Seattle, vigorous, healthy, shade tolerant, and its blooms are amazing. I got one band last year, and now it is 4'x3' with strong basal shoots. I also love New Dawn very much, but after the first flush, it tends to get some rust here. I don't spray. I just remove the infected leaves while pruning in summer. Another climber I grow is Madame Alfred Carrière. She is fragrant and remontant, never balling in the rain, but she's indeed susceptible to mildew. She is vigorous as well and took only one year to grow from a band to a 5' tall bush. These three are fast growers and need lots of space.
I have another 4 climbers, Quicksilver, Jeanne Lajoie, Renae and Ash Wednesday. Quicksilver is a healthy beauty here and my only complaint is that she is a bit stingy here. Spring flush is wonderful and long-lasting, but I hardly get the second round. Jeanne Lajoie lost all her leaves in my garden. I can only guess she doesn't like my microclimate even though she gets full sun. Renae seems to be loved by everyone, but she doesn't love me. She's covered with BS here. Ash Wednesday has my favorite color. but she is prone to mildew too. I may give the latter 3 another year to decide if they can stay.
This is my experience of growing climbers in Seattle. Be noticed that every garden has different conditions that may change the performance of roses. Since we're in the same area, I would like to know how's your rose going later.