I just bolted the suction cup to my smooth gas cap cover, I figure if I sell the bike i'll have to spend 40 bucks for a new cover but I don't mind. It sits right in front of me and easy to touch and the cord to the fairing plug is a short distance. I wouldn't use suction cup on the windshield, mine kept falling off all the time.
07' HD Road Glide-with training wheels (Tow-pac trike kit)
07' Honda 250 rebel (yeehaw!), 02' Suzuki 650 savage (thumper), 13' Kawasaki 300 Ninja