Near-duplicate content

I want to extract sideline navigation, headers and footers from crawl analysis on screaming frog. That's because they give an inaccurate estimate of duplicate/ near-duplicate content. I can see that screaming frog by default extracts tags like nav and footer. What class/tags/id's do you think should be included (or excluded) in content area? I have been tracing the content I want to omit from counting as duplicate on page source but at one time I ended up extracting the products.

Also, in order to scrap out all duplicates that might cause harm to website search rankings, what is the optimal percentage of duplicates? On screaming frog the threshold by default is 90%

P. S It is a WordPress site