Well, I've heard one breaking day for every 4 cleansing, and I've also heard one breaking day for every 10 cleansing. So I think 6-9 sounds good. I wouldn't think you'd need to stay only on only juice that whole time. Maybe 4-6 on juice, then moving onto whole fruits and then veggies and such? Basically following the plan Burroughs lays out, but extending each phase? But planning on being fully readjusted by 10 days.
Are you trying to drink your juice straight? I always have to water mine down for those first few days. I don't think it would hurt to add some lemonade back in. I'm drooling over the watermelon juice, as I plan to have some of that when I transition.
Good luck! Sure hope those tummy pains go away soon!