How you do that ?
I only suceeded to use maybe 10 female models, 10 male models, 2 cam girls (Maya and the indian girl), and I never find a use for a photomodel...(they don't turn any scene).
I don't play with photomodels either, because of the contract limit. I used to leave my camgirls uncontracted, after rising them to level 10, but with the rival system that is now impossible to do.
My game strategy consists in using CARMEN (teen) and LENA (MILF) as superstars, because they can get stuffed 6 days a week and ask for more, as nymphos. I also eagerly seek other nymphos and eventually use them as superstars too. All other female and male models are their partners, so to speak, and are used only to fill in scene types.
When the time comes, I open personal websites for these nymphos. Ideally I try to put in as many scene types as I can (gangbang, FFFM, etc.). For that you need a studio and a certain number of partner models, for each one of these nymphos, 6 days a week, who can only shoot one, perhaps two scenes each per week.
You might say that shooting 12 videos a month is enough, using every nympho only two weeks a month (6 x 2). But organising the production then becomes a nightmare. Maybe the new production assistant system can help this, I haven't tried it yet.
This means that if you want your nymphos to shoot every week a MMF, BG, FF, FFM, FFFM and Gangbang for example, you need 1+1+2=4 female partners and 3 male models, for each of these nymphos. If you only have LENA and CARMEN, that means 8 female partners and 5-6 male partners (who can alternate scene types throughout the week since they can also fuck everyday and still be happy, provided they like the scenes, which I make them do with the manager feature "increase likeness when shooting a scene type"). But the numbers increase with each nympho you get your hands on.
With this game strategy, you can have a max number of 9 nymphos, i.e. one per studio. That means a total of 9 nymphos, 36 female partners minimum, and 27 male partners (excluding yourself if you play a male MC). 9+36+27 =72. But the new need for variety for webistes, to satisfy fans, means you need in fact more partners of different ethnicity, boob size, etc for each personal nympho website.
All this to say that you can easily bump against the 100 contract limit if you also want enough camgirls (and/or photomodels) to make a profit, since keeping all these contracts (I only play with level 10 models) for porn models is incredibly expensive, as it should be. And of course you can't open any other website, therefore weakening your competitivity with rivals. Even a contract limit risen to 250 for example would be fine, though a minimum in my opinion.
Perhaps include an additional challenge, or a requirement to spend additional money to increase the contract number limit?