Thanks.
Just eyeballed that arrangement; no, too makeshift, you really need a support.
Really, this is made for small front racks of a certain minimum width. It's too wide and the straps aren't long enough to accommodate the Bilenky modified narrow Tubus Fly and the narrow custom rear rack on Matts 1 and 2; it won't work strapped to the saddle rails without a support, and there's no way to strap it to the handlebar that I can figure out.
Before I sell it on, I'd be grateful to see photos of others installation of this very well made little trunk bag. Anyone?
Thanks.