I am doing good at c4s, but it's a full time work (for big $$ )
A lot of shooting, and a lot of research and a lot of trial and error to find what work the best.

To answer your questions:
My niche is Shemale. I started the store with about 15 clips.
I spent about 3 hours originally to get the store setup. After that, about 15 minutes a day.
I have my minimum set to $500, which I haven't reached yet, so no payment yet.
I don't think it's been worth it, but next week I will add a lot more new videos from what she shot this week. Let's see if that makes it worth my time.