Hello,
this would be a very instesting "how-to"-film on YT on this very beautiful wheel. I think they were the forerunners to the rose petal wheels that later were used on the Cooper racing cars and the even later Minilite wheels of which I have a set in 5.5x10 size for Minis in magnesium but not recommended for racing any more as magnesium is prone to aging quite quickly.
Kind regards,
Helmut