How to calculate the contribution to the project with shared ownership?

Question

Work organization

For example, an investor gives 100 thousand rubles. Then two people work together for 3 months (for a share), then another one joins them (for a share), and the three of them work for another 3 months. Then the first one loses faith in the project and leaves, the remaining two continue to work for another three months and finally release the project.

Bonus

All people have different costs in the labor market. That is, their time is not equal.

Bonus 2

After the departure of the first person (the programmer), the team decided to abandon half of his work, because it is easier to rewrite part of the code from scratch to finish all his work.

Bonus 3

Самый первый месяц работы вообще холостой, потому что выбрали не ту архитектуру, пришлось отправить всю проделанную работу в корзину. Но был получен ценный опыт. В каком-то смысле это тоже вклад, хотя опыт личный.

Bonus 4

Идея принадлежит первому. Но без эмоциональной поддержки от второго, первый не смог бы её продумать до конца и оформить.

The project brings income every month (different). Of the remaining people, one is completely lazy and just wants to get money. The other continues to work, develop the project, is engaged in promotion. And after 3 months, another person joins, also in share, but works at half strength, in the evenings (after full-time work in another place).

Bonus

Польза 1 часа работы у разных людей разная. Иногда даже отрицательная польза, когда какое-то решение приводит к уменьшению прибыли в следующем месяце.

How can you not go crazy in this hell and distribute money as fairly as possible so that everyone is satisfied? Including everyone who wanted a share of the project and was somehow involved: money or their time - a contribution. In the example, it turns out 5 people: an investor plus 4 co-authors.
What's the best way to put this into a contract?
The point is that the share is calculated depending on the contribution. Because if the share is calculated at the beginning and does not change, then there is no incentive to make efforts, try to do better, work conscientiously, take the initiative in solving and preventing problems and bugs.

Answer 1

Transfer the share to certain stages - recalculations of the share:
Current contributions (not equity) to accept as an exchange of work for money (not dividends, namely costs). Accordingly, who spends how much time, effort and how efficient an hour is - everything is reflected in the salary.
Just a share is a very slippery moment and it cannot be woven into all aspects, the logic will burst almost immediately
. You can come up with rules for its distribution and time limits - well, for example, in a year everything needs to be redistributed.
This point is flexible in that everyone has a share at the entrance, and at the same time it is not big, and during the life of the project you can donate to those who make a big contribution.
In general, justice cannot be achieved, but transparent rules can be achieved