Thanks, Rob, for answering. We are in Zone 2 at a pretty high elevation in the mountains above Anchorage. I know that R19 isn't going to cut it, however, if it has a lot of airflow, I wouldn't have to spend all the money I am right now on the electric HRV unit to move air in and out of our very tight house now. I like the idea of putting an air space in the middle---cool idea. Or maybe straw/clay in the middle. That breathes.
I will share your responses with folks up here, so that maybe someone will try it out and do the research.