You might have already gotten your
rocket stove figured out but if you still need help you might try contacting Paul and Lisa Majors form Garfield Ar. They built an earth bag home and they heat it with a
rocket stove. They have also held classes on making one. He is also a heating and cooling guy by trade so he understands all the technical stuff. You can google them and find contact info that way. they have some youtube videos etc.