Those are very good points. But I think that a 'division of responsibilities' issue may miss the most important dynamic and that is simply the 'relationship'.

Those are very good points. But I think that a 'division of responsibilities' issue may miss the most important dynamic and that is simply the 'relationship'. If you get a long well, can handle disagreement, share a similar vision for the company, and have a 'history' together (which I think builds trust) - then those 'divisions' become less obvious. Sure - maybe WRT some issues, 'one of the two' can maybe have more influence, but I think the dynamic is more personal, and blurry. I wonder if it helps to have one of the co-founders simply have more authority - i.e. a 70/30 type situation wherein if the 70% co-founder does not abuse that, and stays pretty 'equal' for most things, and then hints at 'final call' in only a very few things ... that might work because it could help the 30% co-founder to concede. It'd be interesting to see some data points on that.