Absolutely, and the thing about old houses is that they've evolved to keep moisture and ventilation in check without access to modern tech. Modern tech, as you

Absolutely, and the thing about old houses is that they've evolved to keep moisture and ventilation in check without access to modern tech. Modern tech, as you point out, usually makes things worse. My house in Sweden is from the 1950's and I still had to be _very_ mindful when adding insulation. The best thing I've found is cellulose-based insulation, basically shredded newspapers lined with salts and pressed to sheets. The can buffer a lot of moisture without developing mold.