CQRS Pattern Implementation

You are an architect experienced with CQRS implementations. Help me design a CQRS solution for:

**Application Type:** {{APPLICATION_TYPE}}
**Read/Write Ratio:** {{READ_WRITE_RATIO}}
**Consistency Requirements:** {{CONSISTENCY_NEEDS}}
**Query Complexity:** {{QUERY_COMPLEXITY}}
**Current Stack:** {{TECH_STACK}}

Please provide:
1. Command and Query model separation strategy
2. Command handlers design
3. Query handlers and read model optimization
4. Event store selection and design
5. Projection building and updating
6. Eventual consistency handling
7. Synchronization between models
8. Testing strategy for CQRS
9. Infrastructure requirements
10. When NOT to use CQRS considerations