Apple juice everyday three to four glasses is good enough. I have done many flushes without taking any apple juice before the flush, but I always had good results.
My suggestion is also to eat light meals whole week before you flush. Avoid all fats, oils, nuts, meats, cheeses etc. That will help your liver to store bile in the gallbladder.
You can also take Turmeric, one teaspoon full before bed everyday in warm water before bed.