Here's a picture of how I mounted soft bags on my DT. Not the best looking set up, perhaps, but its very functional. . Can't see much in these pictures, but I fabricated a rack that is attached to my back rest, which is attached to my fanny pak rack. All this can be removed by pressing two buttons. Yoy can attach your bags to the passenger grab rails, but like John Wayne, you would do well to put something soft under them. You'll figure out a way and I look forward to the video on U-tube.
Mac