[anigbrowl]

From the title I thought this was going to be about a team member who died, glad that's not the case.

He's a bit arrogant but

In any relationship, whatever irritates you at the outset has the potential to become a real source of resentment later, so be clear about where your boundaries are.

A lot depends on how much work this potential partner is proposing to put in before bringing in the big bucks and potentially cashing out. But putting all those meta considerations aside, if you want 30%, he wants 40%, and you really feel he has something you don't which would be hard to find elsewhere, 33 1/3% seems like the natural inflection point.

[co-park]

Sorry, my working was confusing: what I meant to say was I wanted to give him 30% while I keep 70%, but he wants 40%

[anigbrowl]

Oh that came through clearly. I meant if you really want him maybe you can go up to 33%, assuming all the other indicators line up for you.