I would get the 12' frame and have it assembled when the frame is put together the first time. I bought a 10' frame with the 2' extension. When they were setting up the frame and machine I told them not to add the extension (we would add it later). BIG MISTAKE! We had to completely dis-assemble everything to add the extension to the MIDDLE of the frame (we thought it went on one end). But now we know how to set it completely up, machine and all!