Ask HN: How much equity to give to developer (pseudo-founding)?

Hey Guys,

About to begin production on a project, and rather than take cash I offered, the developer I am working with would like an equity stake. Currently, there are two founders who are putting in money, and one doing all practical (management) and creative (customer facing, UI/UX/collateral and so on) things.

Still uncertain if developer will be a founding CTO or just a contract developer. Perhaps you guys can help me with an answer for both scenarios?

Many thanks.