I made the adjustments you suggested, and I do see the desired changes for the most part.
However, I checked and what I believe is my longest page is nearly 700000 characters long (http://premadharma.org/revealed-truth/). I adjusted the setting in the backend accordingly, and now if I run a search for the phrase “the swan of your heart”, which occurs near the bottom of this page, then the search function does not find the phrase, but if I click on in the front-end settings, “search for exact matches only” then it finds the correct page but it does not highlight the text.
Is there anything more I can do so that it highlights the exact match?