The more I learn about this, the more there is to learn. When you get outside of code minimums, rules of thumb, and old habits, research is needed. After reading an article last November on the science of how vapor drive and condensation relate to where insulation is placed, I studied some key wall construction details to see if I could understand how winter design conditions could be used to develop the most effective wall for a given climate. I felt that I got it right, but questions remain. I still need to learn more, not the least of which is how much more such a wall would cost compared with a "conventional" wall, and what the energy savings ROI could be.