for now, I mounted 2 17ltr each soft textile bags. they connect via 3 velcro straps over the passenger seat, under the passengers butt. the butt that rides on that seat in my case says its no hindrance.To be on the safe side, I mounted 2 delrin plates underneath, which I bolted to the passenger handrails with 4xm8, but 1/4 inch longer than the originals, since the plates are 1/4. For the plates I used cutting bords from the kitchen dept. of a department stores.
additionally, under the driver seat there are 2 elongated openings in the steel of the frame. I ran a strap with a tight sewn loop thru there
and around the rear shock , than out the other hole. this strap exits where the seat touches the plastic cover, between the crotch area.
Than I attached the regular motorcycle tankbag to this strap, and also sewed myself 2 straps over the handlebar to hold the forward end of bag.
Longerterm, I am just now cutting 2 pieces of aluminum, which will be attached to the same bolts, but run back and up, and above, the rear lights. There, they are beeing attached via bolts and 1 inchx 1 inch
rightangle, to a plate which sits behind the backrest. To that I am bolting the GIVI mounting plate from my Monolock Topcase. Simple.
Regards, Peter in bretzelcountry