One practical use of orbit levels is determining how balanced the community is. By balanced, we mean that there are enough people in the right levels to propel the community's mission forward in an effective way, and to create as much gravity as possible in the process.
When a community is out of balance, it is leaving opportunity on the table. For example, if a community has 10 Advocates but only 5 Contributors, there is a lost opportunity for Advocates to support and mentor more Contributors, to help maintain a strong pipeline for future Advocates as the community evolves.
As another example, a community may have just a few Advocates and Contributors supporting hundreds or thousands of Participants and Explorers. In some cases this may be okay, but it's likely that the community could work faster toward its mission, and avoid overstressing its inner circles, by working to help some Participants become Contributors and Advocates.
When starting with the Orbit Model, we recommend that you first sit down and describe your orbit levels and the patterns associated with them. As a next step, we recommend writing out what you believe is an ideal balance between the orbit levels you've defined. There's no right or wrong answer, but here are some of the things to optimize for.
Between two levels, what balance will lead to an optimal amount of supporting and mentoring? How many Contributors can an Advocate support and mentor? Think about this between each pair of levels. A community is stronger and more scalable if support and mentoring are happening between members one level apart vs. all mentorship coming from the center.
If growth is a goal of your community, think about the ratios that will make growth sustainable. If your goal is to grow the overall community by 200%, think about how many Advocates and Contributors it will take to support an influx of Participants and Explorers.
Some communities have a clear idea of how much work, and what kind of work, needs to be completed for the community to succeed at its mission. If that's the case for you, think about how many members are needed at each level and what their specific contributions will be. An open source project may know that it needs a handful of core team members (Advocates) and a few dozen Contributors (reviewing and merging PRs) to support hundreds of Participants (opening issues and asking questions) and thousands of Explorers (reading docs and content).