I got a hold of a cheap tank bag, Marsee I think, that has 2 big magnets in the center. The forward one sits on the fuel cap so doesn't do much good, but the rear one holds firmly on the tank. Then, the wide flaps, much like your Cortech, I put a crease in and folded up under the bag until those magnets contacted the metal. At first I was skeptical, but it held perfectly on my last 3500 mile trip. I like the ease of the magnetic bag, simply pick it up and set on seat while fueling. Some may not like the security aspect, but I never had any problems. I may elect not to leave it on the bike in an urban setting however.