More than one hundred, one gets lost in the crowd.
One hundred people is the ideal number between the economy and diseconomy of scale in a sustainable, equal society. Less than one hundred and there's too much and too many things for each person to do. More than one hundred and transportation and management becomes an issue.
To have a sustainable society (fossil fuel free) and an equal society (free of authority), while having the scale necessary to have efficient infrastructure, machinery, technology and specialisation of labour, one hundred people is the ideal number. With open-source sharing and 3D printing, a high-tech, sustainable, equal society is now possible.
For example, let's say two out of every 100 people want to make clothes, but it's uneconomical to make the machinery for just two people. So they get together with the two people who want to make clothes from the 50 villages linked to their town, making 100 people. This works for our core needs but not for specialised things without an expanding circle of 100 people.
For example, let's say one person out of 10,000 wants to have use of a large telescope. But it's uneconomical to make a large telescope for just one person. So they get together with the nearest 100 people via the internet who want use of a large telescope to work out where and how to build one.
One hundred astronomers don't have the resources to build a large telescope, so each astronomer works with the glass/ceramic makers of their town who have their circle of 100 and the engineers who have their circle of 100 and the computer-technician/software-developers who have their 100 and the carpenter/plumber/electricians who have theirs. A total of 40,000 people who can work on the project.