Anyway, You may need a permit. The best thing to do is ask the Building Inspector, if only to have the inspector tell you what the set-backs, (the distance you need to keep the shed from the property line) are. It's a real pain to move it after it's built.
Next, through away the CAD and take out a pencil or better yet, go to a lumber yard or home improvement store and get the plans for what you want or have them help you.
I have no idea what you mean by "native lumber"? I know that Native Americans we used to call "Indians", but that is not politicaly correct. Native to what?
Last of all, Do you own a saw? It does not matter to the saw if you are cutting one inch or six inches. It will be less expensive to buy standard KD lumber and cut it.
Some home improvement stores sell kits that come with pre-cut lumber and a set of plans.
I don't want to sound harsh but, I'm really not sure if this is a real post or not. If it is, I think you need more help than we can provide online with the information you have provided.