I think before you order this stove you should post some pictures of where this porch will be in relation to your home. Why? Chimney draft that’s why. You could get yourself in a down draft situation coming off of your main roof. You want to avoid that. I am confident that if you could at least post some pictures of where your porch will be placed as well as a picture or two from the side of the house showing the main roof, then member @bholler could likely save you some additional headaches on chimney placement, types, proper chimney height, etc.
We all would like to see you happy with your install, and it needs to be right, and it needs to be safe. @bholler and others here are pretty knowledgeable of codes and safety regulations and they can help educate you so that you are better informed when dealing with your salesman.
We all would like to see you happy with your install, and it needs to be right, and it needs to be safe. @bholler and others here are pretty knowledgeable of codes and safety regulations and they can help educate you so that you are better informed when dealing with your salesman.