CPQ Eligibility Rules Limitations

What are the practical and system-defined limitations of Oracle CPQ Eligibility Rules? Specifically:

• Is there a maximum number of SKUs or customers that can be handled effectively using eligibility rules?
• Can eligibility rules be extended or customized to reference external data sources like Data Tables for dynamic conditions?
• Are there any performance or scalability considerations when eligibility rules are used for large volumes (e.g., hundreds of SKUs or multiple customers)?
• Does Oracle recommend a threshold beyond which a different approach (like Data Tables or custom logic) should be used?