Yup it's a different game when in a firm. However, one-on-one interactions IMO can be based on 50/50 - tangible or not, I guess I'm just trying to present a mindset of treating each other as equals. Firms are made up of individuals anyway. And yup, uneven splits was address and you're right - 50/50 to get the ball rolling would be the best default before settling onto something fairer for both parties as they get to know each other :)

Complementing each other with personal strengths is good enough justification for a 50/50 collaboration - I'm sure you'd agree with that. Honest market actors will also tend to volunteer shifting the initial 50/50 offer, if one side is generally more skillful or reputable.