I haven't read all of this thread so FWIW, I have a Hornig tank bag. Got it from F800 Depot. Works great and the fit is perfect, but should have a rain cover. Cover is available in Europe and would cost about $90 to get one here. Front attachment is awkward and rear is basically permanent. When I ride without the bag, I have to tuck the straps under the front of the seat. I also got a horn button protection switch, which is nice.