I cannot comment 'cause I'm completely out of my element in this. I'd guess I would have to buy the pieces, parts that were available - be it repro or original. And then meld the 2 together. But you already know that part. And you're so much better at this than myself.
I'll have a go at doing this type of work at my uncles 48 F-1 in the near future. So by you sharing the experiences you're helping more than you know. As always, thanks for taking us along for the ride! 8-)