I see what you mean and I don't envy you. Did you read the "manage grazing" article?
Strip grazing sounds reasonable enough for summer. You can also have your grass tested for NSC, so you know what you're dealing with for a start.
Also, having your horse(s) tested for Insuline Resistance is a good idea.
And Google "magnesium for horses elektralife", that's the article I was talking about earlier, can't post a PDF with this phone, sorry.
It is manageable, it's just a matter of knowing how
I could have my grass tested but I'll have to get lots of samples. We have sooo many different kinds of grass out there.
Will check out the magnesium article.