Hi Jim,
Tubeless. I had new rims made for me by Wheelsmith.
16"x6" w/3.5" backspace. If I were to have them made again I'd have made them 16"x5" which would be closer to the original width of 4.5".
However, If you have good, straight rims, there's no reason you shouldn't be able to use tubeless tires. My '39 Packard runs tubeless radials on the original 16"x4" wheels without leaks or blowouts.
If you're worried about leaks, I know two people who have coated the inside of their original, two-piece, riveted rims with Flex Seal in order to run tubeless tires without losing air. It works very well.
