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.
In writing almost same as paraphrasing, article rewriter tool & essay rewriter tool works, but as writer we need to know clearly what are the differences of between two. In article rewriting you can change the word or phrase to keep the meaning same as well may add few more sentences to elaborate the matter more clearly to the reader. Rewritertools.com tried to present few essay rewriter tools for make the writings easier and comfortable.
Quality readable content is key here. Google, for example, will recognize that people are leaving your site soon after arriving if they perceive that your site or blog is full of junk content. This is called "bounce rate." If your bounce rate is high, then people are quickly leaving your site. But for the sake of your business, to build your online reputation and brand, you want people to visit your site, stay for a while, and then keep revisiting over the long term.
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.