I prefer long term cooperation, my reward expectation depends on it.
In my imagination, the highest priority is to build up a very good concept, implement it, advertise it, build a strong community and the financial rewards are coming after all these steps. If we get through all of these, I would like to have a piece of the cake as well.
The main principle is to be fair with each other.
On the other hand, if somebody would contact me like "hey, you will be the only developer and let's do this and that" - to me this doesn't sound like fair, so I would ask for financial rewards for everything I do. This case is pure work, the case above is kind of a knowledge sharing within the developer team, it is even fun. This isn't.
I hope this is clear.
Thank you for your question, it was a pretty good one!