My thoughts exactly. The piedmont soils, climate, and elevation (700-1200 feet above sea level) are perfect for Fortunei. After seeing what t. fortunei can look like up here I wouldn't want to grow them further south!
Interestingly, the only place in Florida I've ever seen fortunei look good is Tallahassee, which is located in an intrusion of piedmont-type soils, and even has some terrain (although not much elevation). Piedmont species such as rhododendron minus, mountain laurel, and several hardwood species have their southern most populations in the forests nearby, while pre-ice age Appalachian flora such as torreya were able to escape glaciation and hang on until the present day.