This is so helpful for both practice and studying for the ARE - thank you for taking the time to share your wisdom with the community @coachchrishopstock!
A piece of advice I was given when I designed my first exterior wall assembly was that you must:
- Do what you can to prevent water from entering the wall assembly, and
- Know that water/vapor will enter the wall assembly, so you must make sure that it has a way to get out.
The first point is a given, but the second point was surprising to me at first and has always stuck with me as a reminder of how a successful wall assembly should function. Hope for the best, prepare for the worst 
Kiara Galicinao, AIA, NCARB
Product Coordinator
Black Spectacles