Windows on Wash, I am leaving those gable vents open! You've been a great help.
GBR in WA, great links! Zone 6-7 is wishful thinking for Minnesota. We're mostly Zone 4 here. I will definitely use the cooler temps this fall to further air seal the attic floor. Fortunately I have no plans to use the attic so if I can just prevent moisture problems up there, I'll be a happy camper. I have lots of reading to do.
I really appreciate all the advice! It's been an eye-opening education and I needed it.