If you have an idea, and you know a fellow co-founder that's interested in starting up - Just start it with him and work together.
Bottom line: Instead of thinking about the non-essential stuff- Just get the first prototype up even if it might mean doing it yourself.
Any school of thoughts that places restrictions on an ideal founding team size is crap. The debate that advocates an optimum team size is no different from saying that man cannot complete a mile in under 4 minutes.
Work with what you have, not what you don't have.