More people are more worried with dehydration and are glad that we found out from Andreas that we can drink water till 20 min. before the ES. I don't know what flush you are talking about, but it does not sound different from the average flush.
Why don't you know just stick with the flush instead of adding garlic. When you start changing things you will later never know if it was because you added something extra or if it was the original flush that things worked or did not work.