Ask HN: Fair share deal between me and my cofounder

Hi, let me quickly explain my situation. I quit my job in March this year and started working on creating a prototype which is nearly ready to launch now (we just need a few more servers). During that time I exchanged the ideas I had with a friend of mine. He quit his job 3 months afer I do and after I finished the prototype (he probably wouldn't have quit his job if he hadn't seen the prototype working). The inital impuls, ideas and also the ideas we are now following all come from me. I also relocated back to my hometown. We also got accepted in an incubator and got free offices and coaching for at least 4 months, which I would say, is mainly because of the working prototype I created. We are probably exploring two different business ideas at the same time. One idea is a pure search related web startup. For that case I definitely don't need my cofounder (as he is more the business guy), and if I would like to have a cofounder for that part, I would definitely like a technical person. In addition to that we are exploring a more tradional business (we are resuing the software I created to sell a service to local companies). This one requires selling stuff to people and this is where my cofounder comes in. I'm pretty sure I can't do both things alone. Anyway, for the second type of business there are two parts. The technial one (I nearly completed) and the selling part, which then has to be completed. Now, I don't know if my cofounder is even good at doing this (as he doesn't have any experience doing this (worked in consulting business), is still relatively youg as I am, and probably doesn't ahve many connections, and I also don't know him very well). If he would fail, I would end up not only losing money, but also time (which is the most precious), even though I probably would have fullfilled my part. My idea was to let us both invest an initial sum of x into our company and we both wouldn't take out any salary out of it in the first months. In addition, the 3 months revenues (let's say y, a little bigger than x) I lost from quitting my job earlier than he did (as he was still earning money at that time) are virtually added to the sum I'm investing. In addition there is also risk of quitting the job first and creating the prototype, idea, relocating and the incubator which I would like to weight somehow as well. But I'm not yet sure on how much this is worth. Also there is the risk that he doesn't sell anything at all. In that case I would like to get rid of him, as he is simply wasting my time. So my idea on this part is to make a deal that if he doesn't manage to get that many customers and doesn't generate that much revenue in a given time frame, he simply has to hand over his shares to me. In that case I could still contine business idea 1 or even consider going further with business idea 2, depeding if there is still a chance. I would however have lost a lot of time (also explaining things to him and discussing things...). The easiest possibility would be to only overwrite him his shares if he reaches his goal, instead of taking them from him away (from a legal view). But I don't think he will agree with that one. I was thinking of a 65:35 deal (alone moneywise it would be more like 2.2:1, let alone the imaterial things I didn't add, like the idea, risk, etc...), but I think it is too high. But if he manages to get us profitable by the end of year, I find it is ok as I also benefit from it, allthough I took a much higher risk than he did (also timewise). Another related question. Is it common that all shareholders have to agree to sell a company or is this more uncommon? What are your thoughts on this? Is there something I forgot and I should pay attention to?