Skilled Shirt Designer For Already Succesful Niche Shop

I have a niche shop up and running and boost my designs massively via ads. I am looking for a skilled designer who can deliver amazing designs based on my ideas, layouts and briefings. All designs focus on one particular niche. I am very willing to share the success with a reliable designer. I would like to start paying per design and depending on the outcome hire a partner for fulltime designing.