[Kurt in NJ]

Find someplace that does teapots and try them
Or buy new ones from brattons that have modern reflective material
If you are going to use regular bulbs look for old stock, there's no workmanship in modern ones I have seen, the filaments don't look like the placement the original ones have, this will affect focus
About 25 feet away without the lens the focus is adjusted to give a spot about basketball sized, if reflector is properly shaped, then with lens on you will get the best light it can do--- for me stop signs show up at .3 to a half mile away, and am comfortable driving at 50 on moonless nights