I tried these settings and was sliding all over. I quit when I was in 5th place after 6 laps. Restarted using default settings (except with ASM off and tramsission set to 34) and my lap times were about 7 sec better -- ended up lapping everybody twice with an old engine and dirty oil (774 HP).
Auto Set 34 is perfect, but Seattle is the last place you want low downforce in the back.