There are lots of ways to promote single model sites, and surprisingly I usually only see them submitted to Amateur And Coed/Teen. There's the type of action, which could be cumshots, hardcore, movies, anal, oral, lesbian, etc., then on many LLs including mine you could submit to the cat for the model's hair color, the cat for what she's wearing in a certain set.
If I were you, I'd look at what niche each individual set of pics falls best into and submit it there, as long as there's some support on the tour for that niche. Spread your submits across a bunch of categories instead of just relying on one or two that are oversaturated to begin with
