Donut Chart
Donut charts reserve the center for a total or short summary. Place VisDonut inside VisSingleContainer; ChartRoot still supplies palette variables, tooltip configuration, and legend metadata.
Summary
Use the central label for a concise total and keep the surrounding legend visible. Segment tooltips can use ChartTooltip with :targets="[Donut]".
Thin ring
A thin ring gives more visual weight to the central number. Rounded corners and slight padding work best with a small number of segments.
Progress gauge
A half donut can present progress against a fixed total. Include both used and available segments so the geometry still represents the complete denominator.
Do not use the central label for a second, unrelated metric. It should summarize the ring or provide the total represented by its segments.