It would help to know where you are located as different countries have different rules when it comes to running your own business either full time or part time next to a "normal" job.
As catfights - no matter how real or scripted they are - put the models health at risk you must have them sign a proper contract. It just takes a clumsy move while not having warmed up your muscles and there is your torn ACL which can get quite expensive depending on the health insurance system of the country you're in. I heard people are against health insurance in the USA, so...
Your best bet would be to invest money and let a lawyer set up a standard contract for the models. Depending on how fit you are with business laws etc. it might help to have a lawyer look at your imprint etc. and you have to know the basics of accounting and other business related stuff.
If you have all that sorted you can start building the website/opening the clips4sales store and think about scripts and hiring models