You may need to contact Steve regarding your question on the door.
As for the jerky drier, I made my own and use it when I am smoking sausage that I make or salmon, food that I am smoking at lower temps. It works well and was easy and cheap to make.
Someone on the board posted instructions on how to make the fan, it should come up through a search and you can see if it’s something you want to try to build or purchase.
Otherwise, you’ll love the 3D! I have the base model and love it!