At 215 m², I would challenge the assumption that the studio is automatically the simpler option. Its floor area could still mean substantial energy and interior-maintenance costs, plus exposure to shared-building decisions.
Ask for the building’s recent budgets, reserve position, planned work...
The most useful timing may depend on whether the inspector can attend before final finishes. Drainage and insulation are harder to assess once relevant areas are covered, whereas paint, doors, fittings and other finish defects are easier to record at handover. Ask prospective inspectors what...