Unless oNe of you is coming to the project having done a significant amount of work (product development or research) then I'd just go with 50/50. Just do it.

Unless oNe of you is coming to the project having done a significant amount of work (product development or research) then I'd just go with 50/50. Just do it. If you agonise about 10% or so either way, it'll just be a bone of contention and one of you will resent the other. Assuming you're both going to be doing the same amount of work (I.e. You're both full time), it's difficult to argue that you should come up with some more fine grained split.