I am looking for a good headlight reflector for 1913-14 Model T.
Welcome to the forum. David, you might do better if you posted this in the classifieds. Some people look there but not here. Also you might say what brand of lights you need the reflector for, I don't think all are the same. You can also buy the replacement style for some brands from the parts sellers.
I was wandering thru Wally-World with my wife not long ago and saw a ladies magnifying make-up mirror for sale for about $5 that looked like the approximate diameter. It was a curved parabolic mirror similar to what was used in gas headlamps. Wonder if something like that would be a suitable replacement? Don't believe the curve on the glass was as deep as originals but appearance-wise it might be an improvement on the polished metal replacements. I may go buy a couple and try them in a couple of unrestored gas lamps to see how it works out. If so, it's a cheap alternative.
I think the Jno. Browns use a 6" reflector. They are quite hard to find. I'm pretty sure the E&J use a smaller size.