Acutally, I took mine out through the right rear door. Haro'* went through the right front and JDB'* went out the same but he removed the door. I guess there is no right way to do it... just what you feel is the best.
From what I understand about leather, different parts of the cow hides have different quality leather. Different textures too. You'll probably need a full hide because of the odd shape it has after it is removed from the cow if you want a seamless headliner. So you are going to see differences from place to place and it'* going to cost $150-$200. That'* what they make vinyl for.
I have an auto trim shop close to me and they must have 50+ different rolls of headliner fabric. You just have to look in the right place.