You can create posters up to 10 x 10 meters (over 30 x 30 feet).
According to tutorials from RonyaSoft , the workflow is built for speed: RonyaSoft Poster Printer 3.2.20
Transform Your Standard Printer into a Giant Billboard Maker: A Guide to RonyaSoft Poster Printer 3.2.20 You can create posters up to 10 x