I have Hellas on my car. They are about 5 or 6 inches in diameter.
They are mounted via holes in the bumpers in a position near the outter most portion of the grill opening. The lamps have a post and retaining nut for mounting. Mine are wired to a toggle switch mounted below the dash on the left side of the steering wheel.
The original owner actually had Lucus square 8's on the car. These are the rectangular lamps as seen on Shelby mustangs of the 60's. The shape of these lamps did not go with the car, so I found a pair of period Hellas. My preference would be for no fog lamps, but I would need to find new bumpers without holes and at about $40 for the pair of Hellas, the lamps and existing bumper saved me at least a grand.
I don't have photos, but will try to take some and see if I can figure out how to post them.
Regards,
Stan