I am using MS Project and OmniPlan.
I work alone, and right know in my plan there are several tasks that can be tackled simultaneously (for example, looking in internet for a street local, to investigate about decoration, investigate about electronics, and to go to the town house in order to ask some questions about the street local permissions).
I want the Gantt diagram to assign 8h between the 4 tasks. So I work 2h in each. But also, when one of the tasks finish, to share 8/3=2.6 hours to the 3 tasks.
By following this logic, this way of calculation should take the same amount of time than the standard: "only 1 task at the same time", in order to calculate the project finish date.
I've seen I can adjust a % to a task. But I don't want a fixed %, I want the program to share my available working time. Right now I am out of ideas.