Help with duplicates

Hello, I would like to have some clarification regarding duplicates, specifically:

• Should I mark a page as a duplicate only when it is exactly the same as another, word for word, or even when it is the same website but with different wording?
• If a result is exactly the same as another, but one of the result blocks is accompanied by images or other content, which one should I mark as a duplicate, and which one should have the higher page quality rating?
• Should I mark as duplicate a page that is already marked with "same as" (ex: Same as R1)?

Thank you very much to anyone who can help me