I don't think you'd have trouble achieving the precision you require. I would assume that in a cosmetic field like jewelery, if you can make the part, you can make the tool (as long as you're not _too_ fussy). Naturally the repeatability is excellent...
I believe it would be possible to make a system (standard die shoes, punch retainers, die buttons, etc.) where you could actually produce a short run of parts more quickly using the die than making each part by hand (building the tooling included). However, for the most part, the effort probably would still not be worth it given the quantities and variety of work you do.
Interesting to consider. There's quite a bit of money in making short run tooling inexpensively...
Regards,
Robin