Help sourcing crown, winding stem, and crystal for Universal Geneve Ferrovie Dello Stato Mk 2

Hi, guys.

Picked up a gorgeous Ferrovie Dello Stato Mark 2 for cheap on eBay. The crystal has been replaced with mineral glass and the crown and stem are generic. The crown is sort of separate from the case due to the stem being too long, which makes me think it’s only a matter of time before the thing gets bent.

I am trying to source at least a crown and stem for this watch, but would also pick up a crystal if I could find one. I don’t mind the crystal I have but it’s mineral glass and has a scratch I need to buff out.

I have read that Cal 64 is virtually identical to Cal 1200. Questions:

1. Does anyone know if the Cal 1200 stem will work for a Cal 64? It looks like these are easier to find.

2. Does anyone know how to size a crown and stem for this watch? Totally new at this. I have seen a few crowns online for sale that do not specify which caliber it went to, but that seem to look like the crown that went to this watch originally. (A plain U on a domed crown)

3. Does anyone know what size crystal this took?

4. Any tips on trying to source parts to bring this thing a little closer to what it was originally?

Thanks for your help.