I am not sure about the ACV dosage, but another option you can look into is Malic Acid supplements. I have found this to be the easiest way so I can avoid drinking apple juice and ACV (hate the taste of both).
I take two pills in the morning and two at night with 16 oz of water for five days before the flush. And on the day of the flush, the sixth day, I take all four together in the morning.
Also make sure the supplement is only Malic Acid, and not a combination of Malic and magnesium stearate. I use the one from Nature’s Life.