Hi Tom,
I think this video maybe of interest.
https://www.youtube.com/watch?v=Y00EEeZC4x4&list=PLCoK1Ao0T01KhfestF7xCic1jf5YjXiVh&index=13

As a test I took your model into blender and was able to pick gems from the JewelCraft addon
and place them on the surface of your model.
Also you can add the prongs as and where you want.
Anyway I think it's worth a look.
Cheers
Barry