Fair equity compensation for team?

I have a colleague who would like to do some work for my startup, equaling maybe 5-10 hours per week. We discussed doing the work for a small, vesting, equity trade. Is there a traditional amount given or expected for this? Common or preferred? He is an extremely talented Rails developer and front-end designer. We bond completely on the vision and I have worked with him for years at work (day job). Advice would be appreciated.