I agree with another comment posted here. If you are confident your work will generate a huge sum of money, and they haven't yet paid you, I'd ask for an equity

I agree with another comment posted here. If you are confident your work will generate a huge sum of money, and they haven't yet paid you, I'd ask for an equity stake with similar terms to the owners' stake (don't get screwed with an inferior share type). Do not deliver the work until you get paid or they give you equity.