Rapid, Regular, Stable — matched to real risk tolerance.
A maintenance exclusion set after an upgrade starts doesn't undo work already in progress.
RapidNewest versions — test clusters only
RegularBalanced — Meridian's staging/prod default
StableMost conservative, longest-validated
Incident-critical: set a maintenance exclusion BEFORE a high-risk traffic window begins — once GKE has started an upgrade, an exclusion added after the fact does not pause it.