What NEWTs do you think a student would take if they wanted to be a potions master? What post-Hogwarts work do you think they would have to do?

I know potions, of course, would be required and I was thinking Herbology too, since that's where you get your ingredients. Care of Magical Creatures maybe?

And after Hogwarts, I was thinking an apprenticeship and then they'd have to produce some new potion perhaps? Or pass some sort of test? Submit some form saying they completed the apprenticeship to the Ministry to become a certified potions master?

Any and all ideas would help!