I am planning on getting the Men's Authentic Pea Coat from Sterlingwear but i cant decide between getting the form fitting jacket or sizing up as I don't know how tight the form fitting jacket is going to be. I am planning on wearing light sweaters and t-shirts underneath this coat and on certain events a suit and a shirt as well. So with this information should I get a form fitting jacket or the bigger version?   Also they asked me to take a jacket that fits me well...