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.
From personal experience Spin Rewriter is the best! like I still use it today. Its so easy to use (Just copy paste and the program do everything) Because of this tool I managed to schedule content and articles for 3 years, do you know how much time and money I’ve saved?!?! A LOT!!! Also i high recommend you pick their mothly plan if you are still in doubt
Readable And Unique Content – the recommended settings for this one are the same as for the one above with the only difference being the change of the 1st input to “Readable”. This will create more unique versions of your content while still keeping a high level of readability. Generally, this is the best setting as it gets a good balance between human readability and uniqueness of the content generated.