The Gardner WS85 Wall Sconce Fly Light should be mounted at 5-6' up as this close to the ideal area flies travel in for best results. A fly's nature is to be below five feet high or even closer to the floor, so this 5-6 feet would be give better results than anything higher.
Yes, the Gardner WS85 Wall Sconce Fly Light does come with all of the necessary mounting hardware.
We would recommend contacting the manufacturer directly for a replacement ballast for the Gardner WS85 Wall Sconce Fly Light. Gardner can be reached at 888-558-1900.