It can be intimidating and "labor intensive," building a decent sized article with block spinning in mind, but it is so fucking worth it. SO FUCKING WORTH IT. That feature alone, could support itself to be sold as a stand alone product.
I'm not a content generator myself, so what I do, is I'll find a POPULAR article, and put it into a raw text editor. Then as the tutorial explained, rewrite the same sentence to mean the same thing. So I rewrite, word for word, each sentence. I do anywhere from two, to five variations. Depending on how early on in the article I am.

Then I break the article up into the blocks that can support themselves as a stand alone blurb (think 50-200 words).
THEN you go in and can manually add your {standard|regular|unique|similar} spintax, to chop the sentences into tiny little pieces. Don't forget to make sure each of the { } are present, and the "use block spinning" is checked. Otherwise you'll break the entire article (without the { }s present)
If you take 1 week and work on it a couple hours a day (depending on the size of the original article), you will have a SUPER SPINABLE article, with virtually ZERO grammar issues. And wherever you want to do keyword stuffing, you can do a keyword, and a bunch of LSI too!
I just finished one that was originally like 800 words. I deleted about 325, as there was a section I didn't want to touch upon, and I went a bit further in depth, and it finished up, as a 2800 word document. This amount, spins into anywhere UPTO 1100 words. I have an intro, and a conclusion, where I keep my link. Everything in the middle is random.
I cant say enough good things about that feature.