I am trying to figure out a way to set it up when I get a new canopy. I was thinking of trying to find one that could suction cup to the window portion of the topper and run rod racks on both sides of the canopy. Haven't found ones that will work yet.
On the window would be too low for me.
You want the rack as high as possible for max clearance and minimum visibility from the outside.
The canopy carpet acts like the "loop" side of the Velcro system.
I would look at the modified shower curtain solution.
The shower curtain that you want is the commercial type that has to be cut to fit. One end is threaded and this is what applies pressure to the opposing walls.
Convert the ends to Velcro "hook".
Wrap the aluminum tubes with tape or non-slip drawer liner.
Pony tail, cloth covered rubber bands are placed over the back tube prior to assembly. These control the butt ends.
A twist tie or the sexier cord stopper + 1/8" shock cord works for the tip ends. There are some heavy duty, reusable twist ties in the hardware stores, now.
There are some pre-built commercial overhead rod rack solutions, but I haven't seen any that I would want.
I especially don't like the sagging, strap type.