[James98]

I believe it is more important to get the correct width, and you should get the widest you can gain suction with. So what is you under bust (rib cage) measurement? i am not clear on what you have been using, but a little wider than what you are currently using. That said I have read about some users of the XL going back to the slightly smaller CL and stating that they felt they got faster progress (and then moving back up later). I also think that if you buy too large and then buy a smaller size it is not a wasted expense because you will move up to the larger size later.
Edit: I was referring to Noogleberry domes.