IMHO
Don't

Nothing says the first is the better version.

Add the count pages Plugin (and configure at least the Pages column)
now you have an additional detail to consider
Next, consider the metadata shown for each. Some, All, mostly cr*p
Now choose, repeat the consider for each book


Use an Intake Library, Use the Find Library Duplicates option before the merge (
Copy to Library: <main one>: Delete )