speaking as the owner of a successful 7 person software consulting firm, its not worth my time to manage you.
We have tried time and time again to try to utilize people for '15 hours on the side'. It fails miserably. You aren't there when I need you to unblock someone looking at your work, and if you have any other commitment, overtime on your main job, a sick kid, a band rehearsal, a stubbed toe, its evident that the '15 hours on the side' is your lowest priority... and that's fine, I mean, I wouldn't give up time with my kids for some beer money on the side, but generally, our priorities don't line up and its only a matter of time before I pay the price.
Contribute to open source, build a portfolio, then determine if its something you're ready to commit to.