Imo it is not possible for google to detect properly spun content, it is not worth computing power it requires. They can do this using ngrams for example, but it is uses a lot of queries. And for example article spinner I coded beats this algo, so google cant detect that the content is spun. Manual spinning is also good but it takes more than 30 minutes per article.
4. Tier 2 content (content that is keyword rich and relevant to your niche. Doesn’t have to be all that readable, it just has to be indexable by a search engine.)– Here put same options as with the Tier 1 content situation with the only difference that you set the 1st input to “Regular.” It is important that lower tiers have a lower quality of content compared to upper tiers.