Photos of all sides, and the garage, too. would be helpful. Many professionals post on this site using Google Sketch Up. It is a way, once you understand how to use it, to create fairly elaborate massing models with enough detail to help you make such decisions. In the hands of a skilled professional, it can come together very effectively. You can download a free version from the web, although the Professional (paid) version has better features. I suggest downloading it first to see how well you can use it. I feel you may find that working with an expert will help you navigate the learning curve more quickly. Happy Houzzing.