Don't know about the 1200 I have one fitted to an 1150 and have the standard panniers. I think Motoworks will be able to tell you as a Ventura agent.
The rack is really useful not only with the bags but also for carrying camping gear, sons exhaust, and other bits and pieces that won't go in panniers. O piece of pipe lagging also makes it a good pillion back support when its all loaded up