I have a 13 wee, so not quite the same, but I made a bracket for the left side and let the right hang over the muffler, used the supplied straps to tie to passenger foot pegs on the front and the license plate frame on the rear.
Note: I put some heavier rear in the right bag at one time causing it to "slump" down slightly. It did melt the heat guard on the back of the bag when it touched the muffler where the heat shield stopped. I thought I was good too, so be cautious.
2013 Vstrom 650. White, CL-855 bags. Bags connection City tankbag. Givi Airflow. Augustus Deflectors. Bar end mirrors. JC Whitney top case.