I was getting headaches too, but found that if drank one glass of water for every glass of lemonade, it helped. Also, I found that senna tea worked better for me than the salt water flush. once in the AM and once in the PM. There's a really yummy brand out called "smooth move". It tastes like Chai tea.
B&P shakes are the Bentonite and Psyllium shakes. I haven't done them yet, but they are explained fully here at the site.