Of the courts, I would say King of Cups because he has the maturity (King) to have the resource base and the sensitivity (Cups) to have an eye for such. Of course, this 'King' could represent a female patron/client.
I would see the 6 Pentacles as a more hands-off art patron - Here, let me give you some money and you go off and do your thing.
I would see the 3 Pentacles as a more hands-on patron - I'm giving you money and I want to make sure your work is up to my standards or specifications.
3 of Pentacles makes sense too. I usually read that as paid skilled labor, or a job that someone enjoys and is well-compensated for, and that could include art.