I just did my very first flush. I don't have any experience in order to give you good advice, but since your question was my big concern also, I just wanted to share my story. Hope it helps.
I adjusted time by 2 hours. I had my doubts also, but thought as soon as I follow protocol (I did Clark's), that should be fine. I didn't want to delay my first liver flush, because I just came off Master-Cleanse fast (4 days ago after 21 fasting). I thought I need to do Liver Flush NOW as long as my body is relatively clean and I don't need to prepare it for several days.
So I had my Epsom Salt at 8 and 10 pm yesterday, olive oil at midnight and two more doses of Epsom Salt this morning (two hous apart). Exactly as someone described earlier.
Let me tell you,I was so surprised! Since it was my very first one, I didn't know what to expect. But it all went so smooth. And since morning I started passing green stones. So far about 200 - different sizes. So I am very happy with results so far.
And now I am happily drinking my fresh OJ!