The general rule I've heard is: no matter what you do, you'll get it wrong. The only variable you can control is how wrong you are.
We're a team of 4, all working part-time, and getting ready to launch. A few other variables in the pipeline (people moving, marriage, etc.) but for the most part, something similar to four equal partners. Three technical, and one non-technical co-founder. SaaS.
Would love your thoughts and insights on how to be least wrong in creating this for the first time.