I have used the sissy bar style on a my bikes. Simple, not fancy or cheap, but effective. Depends how creative you are in finding a place to mount it. They zip tie mount and the flag and pole(1 unit) screw into the mount.
Cost effective - great quality flags as well.
I will see if one will fit on the F6's passenger sissy bar.
I'm no spokes model
http://store.sspflags.com/vehicle-flag-poles/
Jim